21630412 has 12 divisors (see below), whose sum is σ = 38221456. Its totient is φ = 10710000.

The previous prime is 21630391. The next prime is 21630421. The reversal of 21630412 is 21403612.

It is a hoax number, since the sum of its digits (19) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21630412.

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, 25839 + ... + 26662.

Almost surely, 2^21630412 is an apocalyptic number.

It is an amenable number.

21630412 is a deficient number, since it is larger than the sum of its proper divisors (16591044).

21630412 is a wasteful number, since it uses less digits than its factorization.

21630412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52608 (or 52606 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21630412 is about 4650.8506748766. The cubic root of 21630412 is about 278.6259724261.

It can be divided in two parts, 216 and 30412, that added together give a triangular number (30628 = T₂₄₇).

The spelling of 21630412 in words is "twenty-one million, six hundred thirty thousand, four hundred twelve".