21376457 has 4 divisors (see below), whose sum is σ = 21897876. Its totient is φ = 20855040.

The previous prime is 21376447. The next prime is 21376469. The reversal of 21376457 is 75467312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6661561 + 14714896 = 2581^2 + 3836^2 .

It is a cyclic number.

It is not a de Polignac number, because 21376457 - 2¹⁶ = 21310921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21376447) 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, 260648 + ... + 260729.

It is an arithmetic number, because the mean of its divisors is an integer number (5474469).

Almost surely, 2^21376457 is an apocalyptic number.

It is an amenable number.

21376457 is a deficient number, since it is larger than the sum of its proper divisors (521419).

21376457 is an equidigital number, since it uses as much as digits as its factorization.

21376457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521418.

The product of its digits is 35280, while the sum is 35.

The square root of 21376457 is about 4623.4680706154. The cubic root of 21376457 is about 277.5312607155.

The spelling of 21376457 in words is "twenty-one million, three hundred seventy-six thousand, four hundred fifty-seven".