21930072 has 16 divisors (see below), whose sum is σ = 54825240. Its totient is φ = 7310016.

The previous prime is 21929993. The next prime is 21930101. The reversal of 21930072 is 27003912.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 913753 = 21930072 / (2 + 1 + 9 + 3 + 0 + 0 + 7 + 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 456853 + ... + 456900.

Almost surely, 2^21930072 is an apocalyptic number.

It is an amenable number.

21930072 is an abundant number, since it is smaller than the sum of its proper divisors (32895168).

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

21930072 is a wasteful number, since it uses less digits than its factorization.

21930072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913762 (or 913758 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 21930072 is about 4682.9554770465. The cubic root of 21930072 is about 279.9067376471.

Adding to 21930072 its reverse (27003912), we get a palindrome (48933984).

The spelling of 21930072 in words is "twenty-one million, nine hundred thirty thousand, seventy-two".