21636937 has 16 divisors (see below), whose sum is σ = 26358912. Its totient is φ = 17337600.

The previous prime is 21636919. The next prime is 21636943. The reversal of 21636937 is 73963612.

It is not a de Polignac number, because 21636937 - 2⁷ = 21636809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21636896 and 21636905.

It is not an unprimeable number, because it can be changed into a prime (21636907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20062 + ... + 21112.

It is an arithmetic number, because the mean of its divisors is an integer number (1647432).

Almost surely, 2^21636937 is an apocalyptic number.

It is an amenable number.

21636937 is a deficient number, since it is larger than the sum of its proper divisors (4721975).

21636937 is a wasteful number, since it uses less digits than its factorization.

21636937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1248.

The product of its digits is 40824, while the sum is 37.

The square root of 21636937 is about 4651.5521065554. The cubic root of 21636937 is about 278.6539862505.

The spelling of 21636937 in words is "twenty-one million, six hundred thirty-six thousand, nine hundred thirty-seven".