21457051 has 32 divisors (see below), whose sum is σ = 28108800. Its totient is φ = 16364040.

The previous prime is 21457049. The next prime is 21457057. The reversal of 21457051 is 15075412.

It is not a de Polignac number, because 21457051 - 2¹ = 21457049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21457057) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 456510 + ... + 456556.

It is an arithmetic number, because the mean of its divisors is an integer number (878400).

Almost surely, 2^21457051 is an apocalyptic number.

21457051 is a deficient number, since it is larger than the sum of its proper divisors (6651749).

21457051 is an frugal number, since it uses more digits than its factorization.

21457051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 21457051 is about 4632.1756227501. The cubic root of 21457051 is about 277.8796081707.

The spelling of 21457051 in words is "twenty-one million, four hundred fifty-seven thousand, fifty-one".