21925257 has 8 divisors (see below), whose sum is σ = 30953376. Its totient is φ = 13756992.

The previous prime is 21925231. The next prime is 21925261. The reversal of 21925257 is 75252912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21925257 - 2⁷ = 21925129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21925157) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214903 + ... + 215004.

It is an arithmetic number, because the mean of its divisors is an integer number (3869172).

Almost surely, 2^21925257 is an apocalyptic number.

It is an amenable number.

21925257 is a deficient number, since it is larger than the sum of its proper divisors (9028119).

21925257 is a wasteful number, since it uses less digits than its factorization.

21925257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429927.

The product of its digits is 12600, while the sum is 33.

The square root of 21925257 is about 4682.4413504069. The cubic root of 21925257 is about 279.8862505645.

The spelling of 21925257 in words is "twenty-one million, nine hundred twenty-five thousand, two hundred fifty-seven".