21945136 has 40 divisors (see below), whose sum is σ = 43997184. Its totient is φ = 10597440.

The previous prime is 21945101. The next prime is 21945137. The reversal of 21945136 is 63154912.

It is a junction number, because it is equal to n+sod(n) for n = 21945098 and 21945107.

It is not an unprimeable number, because it can be changed into a prime (21945137) 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, 114801 + ... + 114991.

Almost surely, 2^21945136 is an apocalyptic number.

It is an amenable number.

21945136 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

21945136 is a wasteful number, since it uses less digits than its factorization.

21945136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409 (or 403 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 21945136 is about 4684.5635869310. The cubic root of 21945136 is about 279.9708132843.

The spelling of 21945136 in words is "twenty-one million, nine hundred forty-five thousand, one hundred thirty-six".