21992412 has 24 divisors (see below), whose sum is σ = 55263376. Its totient is φ = 6766848.

The previous prime is 21992401. The next prime is 21992417. The reversal of 21992412 is 21429912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21992412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70333 + ... + 70644.

Almost surely, 2^21992412 is an apocalyptic number.

It is an amenable number.

21992412 is an abundant number, since it is smaller than the sum of its proper divisors (33270964).

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

21992412 is a wasteful number, since it uses less digits than its factorization.

21992412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140997 (or 140995 counting only the distinct ones).

The product of its digits is 2592, while the sum is 30.

The square root of 21992412 is about 4689.6068065457. The cubic root of 21992412 is about 280.1717143998.

Subtracting from 21992412 its reverse (21429912), we obtain a square (562500 = 750²).

The spelling of 21992412 in words is "twenty-one million, nine hundred ninety-two thousand, four hundred twelve".