25639680 has 144 divisors (see below), whose sum is σ = 89478144. Its totient is φ = 6205440.

The previous prime is 25639667. The next prime is 25639693. The reversal of 25639680 is 8693652.

It is an interprime number because it is at equal distance from previous prime (25639667) and next prime (25639693).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

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, 41937 + ... + 42543.

It is an arithmetic number, because the mean of its divisors is an integer number (621376).

Almost surely, 2^25639680 is an apocalyptic number.

25639680 is a gapful number since it is divisible by the number (20) 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 25639680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44739072).

25639680 is an abundant number, since it is smaller than the sum of its proper divisors (63838464).

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

25639680 is a wasteful number, since it uses less digits than its factorization.

25639680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642 (or 628 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 25639680 is about 5063.5639622701. The cubic root of 25639680 is about 294.8747145863.

The spelling of 25639680 in words is "twenty-five million, six hundred thirty-nine thousand, six hundred eighty".