21945960 has 48 divisors (see below), whose sum is σ = 71325540. Its totient is φ = 5852160.

The previous prime is 21945943. The next prime is 21945961. The reversal of 21945960 is 6954912.

It can be written as a sum of positive squares in 2 ways, for example, as 18096516 + 3849444 = 4254^2 + 1962^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945961) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30121 + ... + 30840.

Almost surely, 2^21945960 is an apocalyptic number.

21945960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21945960 is an abundant number, since it is smaller than the sum of its proper divisors (49379580).

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

21945960 is a wasteful number, since it uses less digits than its factorization.

21945960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60978 (or 60971 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 21945960 is about 4684.6515345327. The cubic root of 21945960 is about 279.9743173723.

The spelling of 21945960 in words is "twenty-one million, nine hundred forty-five thousand, nine hundred sixty".