25565421 has 32 divisors (see below), whose sum is σ = 40624128. Its totient is φ = 13993920.

The previous prime is 25565413. The next prime is 25565453. The reversal of 25565421 is 12456552.

It is not a de Polignac number, because 25565421 - 2³ = 25565413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25565021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112510 + ... + 112736.

It is an arithmetic number, because the mean of its divisors is an integer number (1269504).

Almost surely, 2^25565421 is an apocalyptic number.

25565421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25565421 is a deficient number, since it is larger than the sum of its proper divisors (15058707).

25565421 is a wasteful number, since it uses less digits than its factorization.

25565421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 441.

The product of its digits is 12000, while the sum is 30.

The square root of 25565421 is about 5056.2259640961. The cubic root of 25565421 is about 294.5897620523.

The spelling of 25565421 in words is "twenty-five million, five hundred sixty-five thousand, four hundred twenty-one".