21994568 has 32 divisors (see below), whose sum is σ = 42154560. Its totient is φ = 10756800.

The previous prime is 21994561. The next prime is 21994589. The reversal of 21994568 is 86549912.

It is a super-2 number, since 2×21994568² = 967522043013248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21994561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131621 + ... + 131787.

It is an arithmetic number, because the mean of its divisors is an integer number (1317330).

Almost surely, 2^21994568 is an apocalyptic number.

It is an amenable number.

21994568 is a deficient number, since it is larger than the sum of its proper divisors (20159992).

21994568 is a wasteful number, since it uses less digits than its factorization.

21994568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437 (or 433 counting only the distinct ones).

The product of its digits is 155520, while the sum is 44.

The square root of 21994568 is about 4689.8366709300. The cubic root of 21994568 is about 280.1808695344.

The spelling of 21994568 in words is "twenty-one million, nine hundred ninety-four thousand, five hundred sixty-eight".