21255732 has 18 divisors (see below), whose sum is σ = 53729858. Its totient is φ = 7085232.

The previous prime is 21255727. The next prime is 21255733. The reversal of 21255732 is 23755212.

It can be written as a sum of positive squares in only one way, i.e., 16353936 + 4901796 = 4044^2 + 2214^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21255732² = 903612285711648, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21255696 and 21255705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255733) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 295183 + ... + 295254.

Almost surely, 2^21255732 is an apocalyptic number.

It is an amenable number.

21255732 is an abundant number, since it is smaller than the sum of its proper divisors (32474126).

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

21255732 is a wasteful number, since it uses less digits than its factorization.

21255732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590447 (or 590442 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 21255732 is about 4610.3939094182. The cubic root of 21255732 is about 277.0078151644.

The spelling of 21255732 in words is "twenty-one million, two hundred fifty-five thousand, seven hundred thirty-two".