21992742 has 16 divisors (see below), whose sum is σ = 48872880. Its totient is φ = 7330896.

The previous prime is 21992723. The next prime is 21992771. The reversal of 21992742 is 24729912.

It is a junction number, because it is equal to n+sod(n) for n = 21992697 and 21992706.

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, 203583 + ... + 203690.

It is an arithmetic number, because the mean of its divisors is an integer number (3054555).

Almost surely, 2^21992742 is an apocalyptic number.

21992742 is an abundant number, since it is smaller than the sum of its proper divisors (26880138).

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

21992742 is a wasteful number, since it uses less digits than its factorization.

21992742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407284 (or 407278 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21992742 is about 4689.6419906001. The cubic root of 21992742 is about 280.1731157347.

The spelling of 21992742 in words is "twenty-one million, nine hundred ninety-two thousand, seven hundred forty-two".