21793399 has 4 divisors (see below), whose sum is σ = 22940440. Its totient is φ = 20646360.

The previous prime is 21793363. The next prime is 21793451. The reversal of 21793399 is 99339712.

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

It is a cyclic number.

It is not a de Polignac number, because 21793399 - 2¹⁷ = 21662327 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 (21793319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 573492 + ... + 573529.

It is an arithmetic number, because the mean of its divisors is an integer number (5735110).

Almost surely, 2^21793399 is an apocalyptic number.

21793399 is a deficient number, since it is larger than the sum of its proper divisors (1147041).

21793399 is a wasteful number, since it uses less digits than its factorization.

21793399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1147040.

The product of its digits is 91854, while the sum is 43.

The square root of 21793399 is about 4668.3400690181. The cubic root of 21793399 is about 279.3240454961.

The spelling of 21793399 in words is "twenty-one million, seven hundred ninety-three thousand, three hundred ninety-nine".