20644545 has 32 divisors (see below), whose sum is σ = 36823680. Its totient is φ = 9815040.

The previous prime is 20644537. The next prime is 20644627. The reversal of 20644545 is 54544602.

It is not a de Polignac number, because 20644545 - 2³ = 20644537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2715 + ... + 6975.

It is an arithmetic number, because the mean of its divisors is an integer number (1150740).

Almost surely, 2^20644545 is an apocalyptic number.

It is an amenable number.

20644545 is a deficient number, since it is larger than the sum of its proper divisors (16179135).

20644545 is a wasteful number, since it uses less digits than its factorization.

20644545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4305.

The product of its (nonzero) digits is 19200, while the sum is 30.

The square root of 20644545 is about 4543.6268552776. The cubic root of 20644545 is about 274.3269269748.

The spelling of 20644545 in words is "twenty million, six hundred forty-four thousand, five hundred forty-five".