21779875 has 24 divisors (see below), whose sum is σ = 29461536. Its totient is φ = 16068000.

The previous prime is 21779861. The next prime is 21779881. The reversal of 21779875 is 57897712.

It is not a de Polignac number, because 21779875 - 2¹¹ = 21777827 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20610 + ... + 21640.

It is an arithmetic number, because the mean of its divisors is an integer number (1227564).

Almost surely, 2^21779875 is an apocalyptic number.

21779875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21779875 is a deficient number, since it is larger than the sum of its proper divisors (7681661).

21779875 is a wasteful number, since it uses less digits than its factorization.

21779875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072 (or 1049 counting only the distinct ones).

The product of its digits is 246960, while the sum is 46.

The square root of 21779875 is about 4666.8913636381. The cubic root of 21779875 is about 279.2662549076.

The spelling of 21779875 in words is "twenty-one million, seven hundred seventy-nine thousand, eight hundred seventy-five".