20905564 has 6 divisors (see below), whose sum is σ = 36584744. Its totient is φ = 10452780.

The previous prime is 20905559. The next prime is 20905579. The reversal of 20905564 is 46550902.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2613192 + ... + 2613199.

Almost surely, 2^20905564 is an apocalyptic number.

It is an amenable number.

20905564 is a deficient number, since it is larger than the sum of its proper divisors (15679180).

20905564 is a wasteful number, since it uses less digits than its factorization.

20905564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5226395 (or 5226393 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20905564 is about 4572.2602725567. The cubic root of 20905564 is about 275.4782378125.

The spelling of 20905564 in words is "twenty million, nine hundred five thousand, five hundred sixty-four".