21375812 has 6 divisors (see below), whose sum is σ = 37407678. Its totient is φ = 10687904.

The previous prime is 21375811. The next prime is 21375821. The reversal of 21375812 is 21857312.

It can be written as a sum of positive squares in only one way, i.e., 20484676 + 891136 = 4526^2 + 944^2 .

It is not an unprimeable number, because it can be changed into a prime (21375811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2671973 + ... + 2671980.

It is an arithmetic number, because the mean of its divisors is an integer number (6234613).

Almost surely, 2^21375812 is an apocalyptic number.

It is an amenable number.

21375812 is a deficient number, since it is larger than the sum of its proper divisors (16031866).

21375812 is a wasteful number, since it uses less digits than its factorization.

21375812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5343957 (or 5343955 counting only the distinct ones).

The product of its digits is 3360, while the sum is 29.

The square root of 21375812 is about 4623.3983172554. The cubic root of 21375812 is about 277.5284693352.

The spelling of 21375812 in words is "twenty-one million, three hundred seventy-five thousand, eight hundred twelve".