21790553 has 4 divisors (see below), whose sum is σ = 21861840. Its totient is φ = 21719268.

The previous prime is 21790541. The next prime is 21790567. The reversal of 21790553 is 35509712.

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 21790553 - 2⁴ = 21790537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21790523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35183 + ... + 35796.

It is an arithmetic number, because the mean of its divisors is an integer number (5465460).

Almost surely, 2^21790553 is an apocalyptic number.

It is an amenable number.

21790553 is a deficient number, since it is larger than the sum of its proper divisors (71287).

21790553 is an equidigital number, since it uses as much as digits as its factorization.

21790553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71286.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 21790553 is about 4668.0352397984. The cubic root of 21790553 is about 279.3118859910.

The spelling of 21790553 in words is "twenty-one million, seven hundred ninety thousand, five hundred fifty-three".