12639640 has 64 divisors (see below), whose sum is σ = 31046400. Its totient is φ = 4603392.

The previous prime is 12639637. The next prime is 12639659. The reversal of 12639640 is 4693621.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 56569 + ... + 56791.

It is an arithmetic number, because the mean of its divisors is an integer number (485100).

Almost surely, 2^12639640 is an apocalyptic number.

12639640 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 12639640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15523200).

12639640 is an abundant number, since it is smaller than the sum of its proper divisors (18406760).

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

12639640 is a wasteful number, since it uses less digits than its factorization.

12639640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 12639640 is about 3555.2271376102. The cubic root of 12639640 is about 232.9404454004.

The spelling of 12639640 in words is "twelve million, six hundred thirty-nine thousand, six hundred forty".