21813902 has 8 divisors (see below), whose sum is σ = 35695512. Its totient is φ = 9915400.

The previous prime is 21813877. The next prime is 21813931. The reversal of 21813902 is 20931812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 495749 + ... + 495792.

It is an arithmetic number, because the mean of its divisors is an integer number (4461939).

Almost surely, 2^21813902 is an apocalyptic number.

21813902 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21813902 is a deficient number, since it is larger than the sum of its proper divisors (13881610).

21813902 is a wasteful number, since it uses less digits than its factorization.

21813902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 991554.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21813902 is about 4670.5355153344. The cubic root of 21813902 is about 279.4116130799.

The spelling of 21813902 in words is "twenty-one million, eight hundred thirteen thousand, nine hundred two".