20981875 has 20 divisors (see below), whose sum is σ = 26710200. Its totient is φ = 16472000.

The previous prime is 20981869. The next prime is 20981887. The reversal of 20981875 is 57818902.

It is not a de Polignac number, because 20981875 - 2³ = 20981867 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 36591 + ... + 37159.

It is an arithmetic number, because the mean of its divisors is an integer number (1335510).

Almost surely, 2^20981875 is an apocalyptic number.

20981875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20981875 is a deficient number, since it is larger than the sum of its proper divisors (5728325).

20981875 is an frugal number, since it uses more digits than its factorization.

20981875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648 (or 633 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 20981875 is about 4580.5976684271. The cubic root of 20981875 is about 275.8130209808.

The spelling of 20981875 in words is "twenty million, nine hundred eighty-one thousand, eight hundred seventy-five".