21405792 has 24 divisors (see below), whose sum is σ = 56190456. Its totient is φ = 7135232.

The previous prime is 21405773. The next prime is 21405803. The reversal of 21405792 is 29750412.

It is a tau number, because it is divible by the number of its divisors (24).

It is a super-2 number, since 2×21405792² = 916415862294528, which contains 22 as substring.

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, 111393 + ... + 111584.

It is an arithmetic number, because the mean of its divisors is an integer number (2341269).

Almost surely, 2^21405792 is an apocalyptic number.

It is an amenable number.

21405792 is an abundant number, since it is smaller than the sum of its proper divisors (34784664).

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

21405792 is a wasteful number, since it uses less digits than its factorization.

21405792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222990 (or 222982 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21405792 is about 4626.6393851261. The cubic root of 21405792 is about 277.6581551181.

The spelling of 21405792 in words is "twenty-one million, four hundred five thousand, seven hundred ninety-two".