1213664256 has 176 divisors, whose sum is σ = 4108410880. Its totient is φ = 346705920.

The previous prime is 1213664251. The next prime is 1213664261. The reversal of 1213664256 is 6524663121.

1213664256 is a `hidden beast` number, since 1 + 2 + 1 + 3 + 6 + 642 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (1213664251) and next prime (1213664261).

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

It is a self number, because there is not a number n which added to its sum of digits gives 1213664256.

It is not an unprimeable number, because it can be changed into a prime (1213664251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 190401 + ... + 196671.

Almost surely, 2^1213664256 is an apocalyptic number.

1213664256 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 1213664256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2054205440).

1213664256 is an abundant number, since it is smaller than the sum of its proper divisors (2894746624).

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

1213664256 is an equidigital number, since it uses as much as digits as its factorization.

1213664256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6307 (or 6283 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 1213664256 is about 34837.6844236238. The cubic root of 1213664256 is about 1066.6768110146.

The spelling of 1213664256 in words is "one billion, two hundred thirteen million, six hundred sixty-four thousand, two hundred fifty-six".