21675620 has 24 divisors (see below), whose sum is σ = 45992184. Its totient is φ = 8580096.

The previous prime is 21675613. The next prime is 21675649. The reversal of 21675620 is 2657612.

It can be written as a sum of positive squares in 4 ways, for example, as 1658944 + 20016676 = 1288^2 + 4474^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3647 + ... + 7526.

It is an arithmetic number, because the mean of its divisors is an integer number (1916341).

Almost surely, 2^21675620 is an apocalyptic number.

21675620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21675620 is an abundant number, since it is smaller than the sum of its proper divisors (24316564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21675620 is a wasteful number, since it uses less digits than its factorization.

21675620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11279 (or 11277 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 21675620 is about 4655.7083241973. The cubic root of 21675620 is about 278.8199486627.

The spelling of 21675620 in words is "twenty-one million, six hundred seventy-five thousand, six hundred twenty".