21885797 has 2 divisors, whose sum is σ = 21885798. Its totient is φ = 21885796.

The previous prime is 21885781. The next prime is 21885803. The reversal of 21885797 is 79758812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15888196 + 5997601 = 3986^2 + 2449^2 .

It is a cyclic number.

It is not a de Polignac number, because 21885797 - 2⁴ = 21885781 is a prime.

It is a super-2 number, since 2×21885797² = 957976220650418, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21885707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942898 + 10942899.

It is an arithmetic number, because the mean of its divisors is an integer number (10942899).

Almost surely, 2^21885797 is an apocalyptic number.

It is an amenable number.

21885797 is a deficient number, since it is larger than the sum of its proper divisors (1).

21885797 is an equidigital number, since it uses as much as digits as its factorization.

21885797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282240, while the sum is 47.

The square root of 21885797 is about 4678.2258389265. The cubic root of 21885797 is about 279.7182412264.

The spelling of 21885797 in words is "twenty-one million, eight hundred eighty-five thousand, seven hundred ninety-seven".