21657055 has 32 divisors (see below), whose sum is σ = 32371200. Its totient is φ = 13571712.

The previous prime is 21657049. The next prime is 21657067. The reversal of 21657055 is 55075612.

It is not a de Polignac number, because 21657055 - 2⁹ = 21656543 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18724 + ... + 19846.

It is an arithmetic number, because the mean of its divisors is an integer number (1011600).

Almost surely, 2^21657055 is an apocalyptic number.

21657055 is a deficient number, since it is larger than the sum of its proper divisors (10714145).

21657055 is a wasteful number, since it uses less digits than its factorization.

21657055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183.

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 21657055 is about 4653.7141081076. The cubic root of 21657055 is about 278.7403235529.

The spelling of 21657055 in words is "twenty-one million, six hundred fifty-seven thousand, fifty-five".