20645644 has 6 divisors (see below), whose sum is σ = 36129884. Its totient is φ = 10322820.

The previous prime is 20645579. The next prime is 20645671. The reversal of 20645644 is 44654602.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2580702 + ... + 2580709.

Almost surely, 2^20645644 is an apocalyptic number.

It is an amenable number.

20645644 is a deficient number, since it is larger than the sum of its proper divisors (15484240).

20645644 is a wasteful number, since it uses less digits than its factorization.

20645644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5161415 (or 5161413 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 31.

The square root of 20645644 is about 4543.7477922966. The cubic root of 20645644 is about 274.3317947650.

The spelling of 20645644 in words is "twenty million, six hundred forty-five thousand, six hundred forty-four".