21820475 has 12 divisors (see below), whose sum is σ = 27123264. Its totient is φ = 17413920.

The previous prime is 21820459. The next prime is 21820481. The reversal of 21820475 is 57402812.

It is not a de Polignac number, because 21820475 - 2⁴ = 21820459 is a prime.

It is a super-2 number, since 2×21820475² = 952266258451250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13142 + ... + 14708.

It is an arithmetic number, because the mean of its divisors is an integer number (2260272).

Almost surely, 2^21820475 is an apocalyptic number.

21820475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21820475 is a deficient number, since it is larger than the sum of its proper divisors (5302789).

21820475 is a wasteful number, since it uses less digits than its factorization.

21820475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2134 (or 2129 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21820475 is about 4671.2391289678. The cubic root of 21820475 is about 279.4396745137.

The spelling of 21820475 in words is "twenty-one million, eight hundred twenty thousand, four hundred seventy-five".