21305692 has 24 divisors (see below), whose sum is σ = 39783744. Its totient is φ = 9948672.

The previous prime is 21305689. The next prime is 21305699. The reversal of 21305692 is 29650312.

It is a self number, because there is not a number n which added to its sum of digits gives 21305692.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8173 + ... + 10459.

It is an arithmetic number, because the mean of its divisors is an integer number (1657656).

Almost surely, 2^21305692 is an apocalyptic number.

It is an amenable number.

21305692 is a deficient number, since it is larger than the sum of its proper divisors (18478052).

21305692 is a wasteful number, since it uses less digits than its factorization.

21305692 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2445 (or 2443 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21305692 is about 4615.8089215218. The cubic root of 21305692 is about 277.2246740306.

The spelling of 21305692 in words is "twenty-one million, three hundred five thousand, six hundred ninety-two".