21812793 has 4 divisors (see below), whose sum is σ = 29083728. Its totient is φ = 14541860.

The previous prime is 21812789. The next prime is 21812821. The reversal of 21812793 is 39721812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21812793 - 2² = 21812789 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21812723) 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, 3635463 + ... + 3635468.

It is an arithmetic number, because the mean of its divisors is an integer number (7270932).

Almost surely, 2^21812793 is an apocalyptic number.

It is an amenable number.

21812793 is a deficient number, since it is larger than the sum of its proper divisors (7270935).

21812793 is an equidigital number, since it uses as much as digits as its factorization.

21812793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7270934.

The product of its digits is 6048, while the sum is 33.

The square root of 21812793 is about 4670.4167908228. The cubic root of 21812793 is about 279.4068779844.

The spelling of 21812793 in words is "twenty-one million, eight hundred twelve thousand, seven hundred ninety-three".