12640403640 has 64 divisors (see below), whose sum is σ = 38198057760. Its totient is φ = 3346165760.

The previous prime is 12640403639. The next prime is 12640403663. The reversal of 12640403640 is 4630404621.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 12640403598 and 12640403607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 368001 + ... + 400880.

Almost surely, 2^12640403640 is an apocalyptic number.

12640403640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12640403640 is an abundant number, since it is smaller than the sum of its proper divisors (25557654120).

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

12640403640 is a wasteful number, since it uses less digits than its factorization.

12640403640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 769032 (or 769028 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The spelling of 12640403640 in words is "twelve billion, six hundred forty million, four hundred three thousand, six hundred forty".