20789865 has 48 divisors (see below), whose sum is σ = 38054016. Its totient is φ = 10886400.

The previous prime is 20789863. The next prime is 20789869. The reversal of 20789865 is 56898702.

20789865 = T₂₈₉ + T₂₉₀ + ... + T₅₂₉.

It is not a de Polignac number, because 20789865 - 2¹ = 20789863 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20789865.

It is not an unprimeable number, because it can be changed into a prime (20789863) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 86145 + ... + 86385.

It is an arithmetic number, because the mean of its divisors is an integer number (792792).

Almost surely, 2^20789865 is an apocalyptic number.

It is an amenable number.

20789865 is a deficient number, since it is larger than the sum of its proper divisors (17264151).

20789865 is an equidigital number, since it uses as much as digits as its factorization.

20789865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332 (or 320 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 20789865 is about 4559.5904421340. The cubic root of 20789865 is about 274.9690984561.

The spelling of 20789865 in words is "twenty million, seven hundred eighty-nine thousand, eight hundred sixty-five".