21336913 has 4 divisors (see below), whose sum is σ = 22978228. Its totient is φ = 19695600.

The previous prime is 21336907. The next prime is 21336961. The reversal of 21336913 is 31963312.

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 12616704 + 8720209 = 3552^2 + 2953^2 .

It is a cyclic number.

It is not a de Polignac number, because 21336913 - 2⁵ = 21336881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21336613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 820638 + ... + 820663.

It is an arithmetic number, because the mean of its divisors is an integer number (5744557).

Almost surely, 2^21336913 is an apocalyptic number.

It is an amenable number.

21336913 is a deficient number, since it is larger than the sum of its proper divisors (1641315).

21336913 is a wasteful number, since it uses less digits than its factorization.

21336913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1641314.

The product of its digits is 2916, while the sum is 28.

The square root of 21336913 is about 4619.1896475464. The cubic root of 21336913 is about 277.3600213867.

The spelling of 21336913 in words is "twenty-one million, three hundred thirty-six thousand, nine hundred thirteen".