12664304640 has 792 divisors, whose sum is σ = 50764208040. Its totient is φ = 3009871872.

The previous prime is 12664304633. The next prime is 12664304641. The reversal of 12664304640 is 4640346621.

12664304640 is a `hidden beast` number, since 1 + 2 + 6 + 6 + 4 + 3 + 0 + 4 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 241864704 + 12422439936 = 15552^2 + 111456^2 .

It is a super-2 number, since 2×12664304640² (a number of 21 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 12664304595 and 12664304604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12664304641) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 436700146 + ... + 436700174.

Almost surely, 2^12664304640 is an apocalyptic number.

12664304640 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 12664304640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25382104020).

12664304640 is an abundant number, since it is smaller than the sum of its proper divisors (38099903400).

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

12664304640 is an frugal number, since it uses more digits than its factorization.

12664304640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The spelling of 12664304640 in words is "twelve billion, six hundred sixty-four million, three hundred four thousand, six hundred forty".