21899812 has 24 divisors (see below), whose sum is σ = 42602112. Its totient is φ = 9765600.

The previous prime is 21899803. The next prime is 21899831.

21899812 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2364 + ... + 7027.

It is an arithmetic number, because the mean of its divisors is an integer number (1775088).

Almost surely, 2^21899812 is an apocalyptic number.

21899812 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21899812 is a deficient number, since it is larger than the sum of its proper divisors (20702300).

21899812 is a wasteful number, since it uses less digits than its factorization.

21899812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9459 (or 9457 counting only the distinct ones).

The product of its digits is 20736, while the sum is 40.

The square root of 21899812 is about 4679.7234961053. The cubic root of 21899812 is about 279.7779361759. Note that the first 3 decimals are identical.

The spelling of 21899812 in words is "twenty-one million, eight hundred ninety-nine thousand, eight hundred twelve".