1221543160 has 128 divisors (see below), whose sum is σ = 3055345920. Its totient is φ = 437501952.

The previous prime is 1221543149. The next prime is 1221543163. The reversal of 1221543160 is 613451221.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221543163) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1182004 + ... + 1183036.

It is an arithmetic number, because the mean of its divisors is an integer number (23869890).

Almost surely, 2^1221543160 is an apocalyptic number.

1221543160 is a gapful number since it is divisible by the number (10) 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 1221543160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1527672960).

1221543160 is an abundant number, since it is smaller than the sum of its proper divisors (1833802760).

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

1221543160 is a wasteful number, since it uses less digits than its factorization.

1221543160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145 (or 1141 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1221543160 is about 34950.5816832853. The cubic root of 1221543160 is about 1068.9800628260.

Adding to 1221543160 its reverse (613451221), we get a palindrome (1834994381).

The spelling of 1221543160 in words is "one billion, two hundred twenty-one million, five hundred forty-three thousand, one hundred sixty".