1221023664 has 60 divisors (see below), whose sum is σ = 3905340816. Its totient is φ = 348863616.

The previous prime is 1221023659. The next prime is 1221023711. The reversal of 1221023664 is 4663201221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 604659 + ... + 606674.

Almost surely, 2^1221023664 is an apocalyptic number.

1221023664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1221023664 is an abundant number, since it is smaller than the sum of its proper divisors (2684317152).

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

1221023664 is a wasteful number, since it uses less digits than its factorization.

1221023664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1211354 (or 1211345 counting only the distinct ones).

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

The square root of 1221023664 is about 34943.1490280999. The cubic root of 1221023664 is about 1068.8285032722.

Adding to 1221023664 its reverse (4663201221), we get a palindrome (5884224885).

The spelling of 1221023664 in words is "one billion, two hundred twenty-one million, twenty-three thousand, six hundred sixty-four".