21945936 has 40 divisors (see below), whose sum is σ = 56960640. Its totient is φ = 7280896.

The previous prime is 21945907. The next prime is 21945943. The reversal of 21945936 is 63954912.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21945894 and 21945903.

It is a congruent number.

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, 10516 + ... + 12428.

It is an arithmetic number, because the mean of its divisors is an integer number (1424016).

Almost surely, 2^21945936 is an apocalyptic number.

It is an amenable number.

21945936 is an abundant number, since it is smaller than the sum of its proper divisors (35014704).

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

21945936 is a wasteful number, since it uses less digits than its factorization.

21945936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2163 (or 2157 counting only the distinct ones).

The product of its digits is 58320, while the sum is 39.

The square root of 21945936 is about 4684.6489729755. The cubic root of 21945936 is about 279.9742153127.

The spelling of 21945936 in words is "twenty-one million, nine hundred forty-five thousand, nine hundred thirty-six".