21755732 has 12 divisors (see below), whose sum is σ = 38271156. Its totient is φ = 10821120.

The previous prime is 21755717. The next prime is 21755761. The reversal of 21755732 is 23755712.

It can be written as a sum of positive squares in 2 ways, for example, as 13205956 + 8549776 = 3634^2 + 2924^2 .

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, 13319 + ... + 14862.

It is an arithmetic number, because the mean of its divisors is an integer number (3189263).

Almost surely, 2^21755732 is an apocalyptic number.

It is an amenable number.

21755732 is a deficient number, since it is larger than the sum of its proper divisors (16515424).

21755732 is a wasteful number, since it uses less digits than its factorization.

21755732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28378 (or 28376 counting only the distinct ones).

The product of its digits is 14700, while the sum is 32.

The square root of 21755732 is about 4664.3040209660. The cubic root of 21755732 is about 279.1630278380.

The spelling of 21755732 in words is "twenty-one million, seven hundred fifty-five thousand, seven hundred thirty-two".