25640632638 has 12 divisors (see below), whose sum is σ = 55554704088. Its totient is φ = 8546877540.

The previous prime is 25640632621. The next prime is 25640632651. The reversal of 25640632638 is 83623604652.

It is a happy number.

25640632638 is a `hidden beast` number, since 2 + 5 + 6 + 4 + 0 + 6 + 3 + 2 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 25640632593 and 25640632602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 712239778 + ... + 712239813.

It is an arithmetic number, because the mean of its divisors is an integer number (4629558674).

Almost surely, 2^25640632638 is an apocalyptic number.

25640632638 is an abundant number, since it is smaller than the sum of its proper divisors (29914071450).

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

25640632638 is a wasteful number, since it uses less digits than its factorization.

25640632638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424479599 (or 1424479596 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 25640632638 in words is "twenty-five billion, six hundred forty million, six hundred thirty-two thousand, six hundred thirty-eight".