20775645 has 72 divisors (see below), whose sum is σ = 42251040. Its totient is φ = 9339840.

The previous prime is 20775631. The next prime is 20775661. The reversal of 20775645 is 54657702.

20775645 is a `hidden beast` number, since 2 + 0 + 7 + 7 + 5 + 645 = 666.

It is not a de Polignac number, because 20775645 - 2⁵ = 20775613 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 442012 + ... + 442058.

It is an arithmetic number, because the mean of its divisors is an integer number (586820).

Almost surely, 2^20775645 is an apocalyptic number.

It is an amenable number.

20775645 is an abundant number, since it is smaller than the sum of its proper divisors (21475395).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20775645 is a wasteful number, since it uses less digits than its factorization.

20775645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135 (or 85 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 36.

The square root of 20775645 is about 4558.0308248190. The cubic root of 20775645 is about 274.9063923828.

The spelling of 20775645 in words is "twenty million, seven hundred seventy-five thousand, six hundred forty-five".