21825989 has 2 divisors, whose sum is σ = 21825990. Its totient is φ = 21825988.

The previous prime is 21825971. The next prime is 21825997. The reversal of 21825989 is 98952812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20775364 + 1050625 = 4558^2 + 1025^2 .

It is a cyclic number.

It is not a de Polignac number, because 21825989 - 2⁸ = 21825733 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21825949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10912994 + 10912995.

It is an arithmetic number, because the mean of its divisors is an integer number (10912995).

Almost surely, 2^21825989 is an apocalyptic number.

It is an amenable number.

21825989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21825989 is an equidigital number, since it uses as much as digits as its factorization.

21825989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 44.

The square root of 21825989 is about 4671.8292991076. The cubic root of 21825989 is about 279.4632105213.

The spelling of 21825989 in words is "twenty-one million, eight hundred twenty-five thousand, nine hundred eighty-nine".