1221617376 has 168 divisors, whose sum is σ = 4121624304. Its totient is φ = 348986880.

The previous prime is 1221617357. The next prime is 1221617387. The reversal of 1221617376 is 6737161221.

It is a happy number.

1221617376 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 617 + 37 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1221617376.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 159556 + ... + 167036.

It is an arithmetic number, because the mean of its divisors is an integer number (24533478).

Almost surely, 2^1221617376 is an apocalyptic number.

1221617376 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221617376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2060812152).

1221617376 is an abundant number, since it is smaller than the sum of its proper divisors (2900006928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221617376 is an frugal number, since it uses more digits than its factorization.

1221617376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7516 (or 7493 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 1221617376 is about 34951.6433948391. The cubic root of 1221617376 is about 1069.0017113496.

Adding to 1221617376 its reverse (6737161221), we get a palindrome (7958778597).

It can be divided in two parts, 12216 and 17376, that added together give a palindrome (29592).

The spelling of 1221617376 in words is "one billion, two hundred twenty-one million, six hundred seventeen thousand, three hundred seventy-six".