21465137 has 2 divisors, whose sum is σ = 21465138. Its totient is φ = 21465136.

The previous prime is 21465131. The next prime is 21465149. The reversal of 21465137 is 73156412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21169201 + 295936 = 4601^2 + 544^2 .

It is a cyclic number.

It is not a de Polignac number, because 21465137 - 2⁴ = 21465121 is a prime.

It is a Chen prime.

It is equal to p_1357544 and since 21465137 and 1357544 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21465131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10732568 + 10732569.

It is an arithmetic number, because the mean of its divisors is an integer number (10732569).

Almost surely, 2^21465137 is an apocalyptic number.

It is an amenable number.

21465137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21465137 is an equidigital number, since it uses as much as digits as its factorization.

21465137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 29.

The square root of 21465137 is about 4633.0483485498. The cubic root of 21465137 is about 277.9145097099.

The spelling of 21465137 in words is "twenty-one million, four hundred sixty-five thousand, one hundred thirty-seven".