21912630 has 16 divisors (see below), whose sum is σ = 52590384. Its totient is φ = 5843360.

The previous prime is 21912623. The next prime is 21912673. The reversal of 21912630 is 3621912.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21912630.

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 7 ways as a sum of consecutive naturals, for example, 365181 + ... + 365240.

It is an arithmetic number, because the mean of its divisors is an integer number (3286899).

Almost surely, 2^21912630 is an apocalyptic number.

21912630 is an abundant number, since it is smaller than the sum of its proper divisors (30677754).

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

21912630 is a wasteful number, since it uses less digits than its factorization.

21912630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730431.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21912630 is about 4681.0928211263. The cubic root of 21912630 is about 279.8325103757.

The spelling of 21912630 in words is "twenty-one million, nine hundred twelve thousand, six hundred thirty".