21365793 has 12 divisors (see below), whose sum is σ = 30920448. Its totient is φ = 14216760.

The previous prime is 21365791. The next prime is 21365801. The reversal of 21365793 is 39756312.

It is not a de Polignac number, because 21365793 - 2¹ = 21365791 is a prime.

It is a super-2 number, since 2×21365793² = 912994221037698, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21365791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3508 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (2576704).

Almost surely, 2^21365793 is an apocalyptic number.

It is an amenable number.

21365793 is a deficient number, since it is larger than the sum of its proper divisors (9554655).

21365793 is a wasteful number, since it uses less digits than its factorization.

21365793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4524 (or 4521 counting only the distinct ones).

The product of its digits is 34020, while the sum is 36.

The square root of 21365793 is about 4622.3146798979. The cubic root of 21365793 is about 277.4851026821.

The spelling of 21365793 in words is "twenty-one million, three hundred sixty-five thousand, seven hundred ninety-three".