25663440 has 80 divisors (see below), whose sum is σ = 86798016. Its totient is φ = 6220800.

The previous prime is 25663399. The next prime is 25663481. The reversal of 25663440 is 4436652.

It is an interprime number because it is at equal distance from previous prime (25663399) and next prime (25663481).

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×25663440² = 1317224305267200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 25663398 and 25663407.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2221 + ... + 7500.

Almost surely, 2^25663440 is an apocalyptic number.

25663440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25663440 is an abundant number, since it is smaller than the sum of its proper divisors (61134576).

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

25663440 is a wasteful number, since it uses less digits than its factorization.

25663440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9748 (or 9742 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 25663440 is about 5065.9095925608. The cubic root of 25663440 is about 294.9657721468.

It can be divided in two parts, 2566 and 3440, that added together give a palindrome (6006).

The spelling of 25663440 in words is "twenty-five million, six hundred sixty-three thousand, four hundred forty".