25639998 has 16 divisors (see below), whose sum is σ = 51355920. Its totient is φ = 8534016.

The previous prime is 25639981. The next prime is 25640023. The reversal of 25639998 is 89993652.

It is a self number, because there is not a number n which added to its sum of digits gives 25639998.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1836 + ... + 7392.

It is an arithmetic number, because the mean of its divisors is an integer number (3209745).

Almost surely, 2^25639998 is an apocalyptic number.

25639998 is an abundant number, since it is smaller than the sum of its proper divisors (25715922).

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

25639998 is a wasteful number, since it uses less digits than its factorization.

25639998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6331.

The product of its digits is 1049760, while the sum is 51.

The square root of 25639998 is about 5063.5953629807. The cubic root of 25639998 is about 294.8759336573.

It can be divided in two parts, 2563 and 9998, that added together give a triangular number (12561 = T₁₅₈).

The spelling of 25639998 in words is "twenty-five million, six hundred thirty-nine thousand, nine hundred ninety-eight".