21813708 has 48 divisors (see below), whose sum is σ = 60053504. Its totient is φ = 6030720.

The previous prime is 21813697. The next prime is 21813709. The reversal of 21813708 is 80731812.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813709) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1585 + ... + 6792.

Almost surely, 2^21813708 is an apocalyptic number.

21813708 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21813708 is an abundant number, since it is smaller than the sum of its proper divisors (38239796).

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

21813708 is a wasteful number, since it uses less digits than its factorization.

21813708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8422 (or 8420 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 21813708 is about 4670.5147467918. The cubic root of 21813708 is about 279.4107847700.

The spelling of 21813708 in words is "twenty-one million, eight hundred thirteen thousand, seven hundred eight".