21812842 has 8 divisors (see below), whose sum is σ = 33009156. Its totient is φ = 10809792.

The previous prime is 21812837. The next prime is 21812863. The reversal of 21812842 is 24821812.

It can be written as a sum of positive squares in 2 ways, for example, as 19793601 + 2019241 = 4449^2 + 1421^2 .

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

It is a super-2 number, since 2×21812842² = 951600152233928, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21812842.

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, 48033 + ... + 48484.

Almost surely, 2^21812842 is an apocalyptic number.

21812842 is a deficient number, since it is larger than the sum of its proper divisors (11196314).

21812842 is a wasteful number, since it uses less digits than its factorization.

21812842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96632.

The product of its digits is 2048, while the sum is 28.

The square root of 21812842 is about 4670.4220366044. The cubic root of 21812842 is about 279.4070872030.

The spelling of 21812842 in words is "twenty-one million, eight hundred twelve thousand, eight hundred forty-two".