25656421 has 4 divisors (see below), whose sum is σ = 29321632. Its totient is φ = 21991212.

The previous prime is 25656409. The next prime is 25656443. The reversal of 25656421 is 12465652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 25656421 - 2²³ = 17267813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25651421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1832595 + ... + 1832608.

It is an arithmetic number, because the mean of its divisors is an integer number (7330408).

Almost surely, 2^25656421 is an apocalyptic number.

It is an amenable number.

25656421 is a deficient number, since it is larger than the sum of its proper divisors (3665211).

25656421 is an equidigital number, since it uses as much as digits as its factorization.

25656421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3665210.

The product of its digits is 14400, while the sum is 31.

The square root of 25656421 is about 5065.2167771972. The cubic root of 25656421 is about 294.9388784602.

The spelling of 25656421 in words is "twenty-five million, six hundred fifty-six thousand, four hundred twenty-one".