21875620 has 24 divisors (see below), whose sum is σ = 49473144. Its totient is φ = 8077056.

The previous prime is 21875611. The next prime is 21875629. The reversal of 21875620 is 2657812.

It is an interprime number because it is at equal distance from previous prime (21875611) and next prime (21875629).

It can be written as a sum of positive squares in 4 ways, for example, as 2090916 + 19784704 = 1446^2 + 4448^2 .

It is not an unprimeable number, because it can be changed into a prime (21875629) by changing a digit.

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, 41809 + ... + 42328.

It is an arithmetic number, because the mean of its divisors is an integer number (2061381).

Almost surely, 2^21875620 is an apocalyptic number.

21875620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21875620 is an abundant number, since it is smaller than the sum of its proper divisors (27597524).

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

21875620 is a wasteful number, since it uses less digits than its factorization.

21875620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84159 (or 84157 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 21875620 is about 4677.1380137858. The cubic root of 21875620 is about 279.6748777321.

The spelling of 21875620 in words is "twenty-one million, eight hundred seventy-five thousand, six hundred twenty".