20642889 has 4 divisors (see below), whose sum is σ = 27523856. Its totient is φ = 13761924.

The previous prime is 20642857. The next prime is 20642899. The reversal of 20642889 is 98824602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20642889 - 2⁵ = 20642857 is a prime.

It is a super-2 number, since 2×20642889² = 852257732532642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20642899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3440479 + ... + 3440484.

It is an arithmetic number, because the mean of its divisors is an integer number (6880964).

Almost surely, 2^20642889 is an apocalyptic number.

It is an amenable number.

20642889 is a deficient number, since it is larger than the sum of its proper divisors (6880967).

20642889 is an equidigital number, since it uses as much as digits as its factorization.

20642889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6880966.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 20642889 is about 4543.4446183485. Note that the first 3 decimals coincide. The cubic root of 20642889 is about 274.3195917435.

The spelling of 20642889 in words is "twenty million, six hundred forty-two thousand, eight hundred eighty-nine".