20997889 has 16 divisors (see below), whose sum is σ = 23721984. Its totient is φ = 18421200.

The previous prime is 20997877. The next prime is 20997901. The reversal of 20997889 is 98879902.

It is an interprime number because it is at equal distance from previous prime (20997877) and next prime (20997901).

It is not a de Polignac number, because 20997889 - 2⁷ = 20997761 is a prime.

It is a super-2 number, since 2×20997889² = 881822684912642, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20997829) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48504 + ... + 48934.

It is an arithmetic number, because the mean of its divisors is an integer number (1482624).

Almost surely, 2^20997889 is an apocalyptic number.

It is an amenable number.

20997889 is a deficient number, since it is larger than the sum of its proper divisors (2724095).

20997889 is a wasteful number, since it uses less digits than its factorization.

20997889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588.

The product of its (nonzero) digits is 653184, while the sum is 52.

The square root of 20997889 is about 4582.3453601840. The cubic root of 20997889 is about 275.8831727427.

The spelling of 20997889 in words is "twenty million, nine hundred ninety-seven thousand, eight hundred eighty-nine".