25640538 has 128 divisors (see below), whose sum is σ = 70778880. Its totient is φ = 5987520.

The previous prime is 25640501. The next prime is 25640543. The reversal of 25640538 is 83504652.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 25640499 and 25640508.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 201831 + ... + 201957.

It is an arithmetic number, because the mean of its divisors is an integer number (552960).

Almost surely, 2^25640538 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25640538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35389440).

25640538 is an abundant number, since it is smaller than the sum of its proper divisors (45138342).

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

25640538 is a wasteful number, since it uses less digits than its factorization.

25640538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192.

The product of its (nonzero) digits is 28800, while the sum is 33.

The square root of 25640538 is about 5063.6486844962. The cubic root of 25640538 is about 294.8780037548.

The spelling of 25640538 in words is "twenty-five million, six hundred forty thousand, five hundred thirty-eight".