21940730 has 24 divisors (see below), whose sum is σ = 45942228. Its totient is φ = 7522368.

The previous prime is 21940729. The next prime is 21940757. The reversal of 21940730 is 3704912.

21940730 = 311² + 312² + ... + 457².

It can be written as a sum of positive squares in 2 ways, for example, as 20638849 + 1301881 = 4543^2 + 1141^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21940730.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21899 + ... + 22878.

Almost surely, 2^21940730 is an apocalyptic number.

21940730 is an abundant number, since it is smaller than the sum of its proper divisors (24001498).

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

21940730 is a wasteful number, since it uses less digits than its factorization.

21940730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44798 (or 44791 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21940730 is about 4684.0932953988. The cubic root of 21940730 is about 279.9520751310.

The spelling of 21940730 in words is "twenty-one million, nine hundred forty thousand, seven hundred thirty".