21812746 has 8 divisors (see below), whose sum is σ = 33255684. Its totient is φ = 10727520.

The previous prime is 21812737. The next prime is 21812759. The reversal of 21812746 is 64721812.

It can be written as a sum of positive squares in 2 ways, for example, as 20802721 + 1010025 = 4561^2 + 1005^2 .

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

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 3 ways as a sum of consecutive naturals, for example, 89275 + ... + 89518.

Almost surely, 2^21812746 is an apocalyptic number.

21812746 is a deficient number, since it is larger than the sum of its proper divisors (11442938).

21812746 is a wasteful number, since it uses less digits than its factorization.

21812746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178856.

The product of its digits is 5376, while the sum is 31.

The square root of 21812746 is about 4670.4117591493. The cubic root of 21812746 is about 279.4066773050.

The spelling of 21812746 in words is "twenty-one million, eight hundred twelve thousand, seven hundred forty-six".