21920589 has 6 divisors (see below), whose sum is σ = 31663086. Its totient is φ = 14613720.

The previous prime is 21920573. The next prime is 21920621. The reversal of 21920589 is 98502912.

It can be written as a sum of positive squares in only one way, i.e., 14402025 + 7518564 = 3795^2 + 2742^2 .

It is not a de Polignac number, because 21920589 - 2⁴ = 21920573 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21920389) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1217802 + ... + 1217819.

It is an arithmetic number, because the mean of its divisors is an integer number (5277181).

Almost surely, 2^21920589 is an apocalyptic number.

It is an amenable number.

21920589 is a deficient number, since it is larger than the sum of its proper divisors (9742497).

21920589 is a wasteful number, since it uses less digits than its factorization.

21920589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2435627 (or 2435624 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21920589 is about 4681.9428659479. The cubic root of 21920589 is about 279.8663860805.

The spelling of 21920589 in words is "twenty-one million, nine hundred twenty thousand, five hundred eighty-nine".