21968442 has 32 divisors (see below), whose sum is σ = 49959360. Its totient is φ = 7151760.

The previous prime is 21968431. The next prime is 21968449. The reversal of 21968442 is 24486912.

It is a super-2 number, since 2×21968442² = 965224887814728, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21968397 and 21968406.

It is not an unprimeable number, because it can be changed into a prime (21968449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2409 + ... + 7052.

It is an arithmetic number, because the mean of its divisors is an integer number (1561230).

Almost surely, 2^21968442 is an apocalyptic number.

21968442 is an abundant number, since it is smaller than the sum of its proper divisors (27990918).

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

21968442 is a wasteful number, since it uses less digits than its factorization.

21968442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9515 (or 9509 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21968442 is about 4687.0504584440. The cubic root of 21968442 is about 280.0698890166.

The spelling of 21968442 in words is "twenty-one million, nine hundred sixty-eight thousand, four hundred forty-two".