21966440 has 16 divisors (see below), whose sum is σ = 49424580. Its totient is φ = 8786560.

The previous prime is 21966401. The next prime is 21966463. The reversal of 21966440 is 4466912.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19412836 + 2553604 = 4406^2 + 1598^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21966397 and 21966406.

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 3 ways as a sum of consecutive naturals, for example, 274541 + ... + 274620.

Almost surely, 2^21966440 is an apocalyptic number.

21966440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21966440 is an abundant number, since it is smaller than the sum of its proper divisors (27458140).

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

21966440 is a wasteful number, since it uses less digits than its factorization.

21966440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549172 (or 549168 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21966440 is about 4686.8368864299. The cubic root of 21966440 is about 280.0613811010.

The spelling of 21966440 in words is "twenty-one million, nine hundred sixty-six thousand, four hundred forty".