21990589 has 2 divisors, whose sum is σ = 21990590. Its totient is φ = 21990588.

The previous prime is 21990557. The next prime is 21990611. The reversal of 21990589 is 98509912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14122564 + 7868025 = 3758^2 + 2805^2 .

It is a cyclic number.

It is not a de Polignac number, because 21990589 - 2⁵ = 21990557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21990509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10995294 + 10995295.

It is an arithmetic number, because the mean of its divisors is an integer number (10995295).

Almost surely, 2^21990589 is an apocalyptic number.

It is an amenable number.

21990589 is a deficient number, since it is larger than the sum of its proper divisors (1).

21990589 is an equidigital number, since it uses as much as digits as its factorization.

21990589 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 21990589 is about 4689.4124365426. The cubic root of 21990589 is about 280.1639728335.

The spelling of 21990589 in words is "twenty-one million, nine hundred ninety thousand, five hundred eighty-nine".