21868812 has 48 divisors (see below), whose sum is σ = 64798720. Its totient is φ = 6248016.

The previous prime is 21868793. The next prime is 21868831. The reversal of 21868812 is 21886812.

It is an interprime number because it is at equal distance from previous prime (21868793) and next prime (21868831).

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13708 + ... + 15219.

Almost surely, 2^21868812 is an apocalyptic number.

It is an amenable number.

21868812 is an abundant number, since it is smaller than the sum of its proper divisors (42929908).

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

21868812 is a wasteful number, since it uses less digits than its factorization.

21868812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28947 (or 28939 counting only the distinct ones).

The product of its digits is 12288, while the sum is 36.

The square root of 21868812 is about 4676.4101616518. The cubic root of 21868812 is about 279.6458618060.

The spelling of 21868812 in words is "twenty-one million, eight hundred sixty-eight thousand, eight hundred twelve".