1221306624 has 216 divisors, whose sum is σ = 3871008960. Its totient is φ = 368603136.

The previous prime is 1221306617. The next prime is 1221306631. The reversal of 1221306624 is 4266031221.

1221306624 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 30 + 6 + 624 = 666.

It is an interprime number because it is at equal distance from previous prime (1221306617) and next prime (1221306631).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1006242 + ... + 1007454.

Almost surely, 2^1221306624 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221306624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1935504480).

1221306624 is an abundant number, since it is smaller than the sum of its proper divisors (2649702336).

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

1221306624 is a wasteful number, since it uses less digits than its factorization.

1221306624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277 (or 1260 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 1221306624 is about 34947.1976558922. The cubic root of 1221306624 is about 1068.9110603274.

Adding to 1221306624 its reverse (4266031221), we get a palindrome (5487337845).

The spelling of 1221306624 in words is "one billion, two hundred twenty-one million, three hundred six thousand, six hundred twenty-four".