21371913 has 12 divisors (see below), whose sum is σ = 31190068. Its totient is φ = 14100480.

The previous prime is 21371893. The next prime is 21371929. The reversal of 21371913 is 31917312.

It can be written as a sum of positive squares in 2 ways, for example, as 3504384 + 17867529 = 1872^2 + 4227^2 .

It is not a de Polignac number, because 21371913 - 2⁵ = 21371881 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371963) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11368 + ... + 13113.

Almost surely, 2^21371913 is an apocalyptic number.

It is an amenable number.

21371913 is a deficient number, since it is larger than the sum of its proper divisors (9818155).

21371913 is a wasteful number, since it uses less digits than its factorization.

21371913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24584 (or 24581 counting only the distinct ones).

The product of its digits is 1134, while the sum is 27.

The square root of 21371913 is about 4622.9766384874. The cubic root of 21371913 is about 277.5115943536.

The spelling of 21371913 in words is "twenty-one million, three hundred seventy-one thousand, nine hundred thirteen".