21812430 has 32 divisors (see below), whose sum is σ = 52596864. Its totient is φ = 5789216.

The previous prime is 21812429. The next prime is 21812447. The reversal of 21812430 is 3421812.

It is a junction number, because it is equal to n+sod(n) for n = 21812397 and 21812406.

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 15 ways as a sum of consecutive naturals, for example, 5209 + ... + 8411.

It is an arithmetic number, because the mean of its divisors is an integer number (1643652).

Almost surely, 2^21812430 is an apocalyptic number.

21812430 is an abundant number, since it is smaller than the sum of its proper divisors (30784434).

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

21812430 is a wasteful number, since it uses less digits than its factorization.

21812430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3440.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21812430 is about 4670.3779290332. The cubic root of 21812430 is about 279.4053280490.

The spelling of 21812430 in words is "twenty-one million, eight hundred twelve thousand, four hundred thirty".