21257332 has 12 divisors (see below), whose sum is σ = 37251396. Its totient is φ = 10614080.

The previous prime is 21257323. The next prime is 21257347. The reversal of 21257332 is 23375212.

It can be written as a sum of positive squares in 2 ways, for example, as 4822416 + 16434916 = 2196^2 + 4054^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21257297 and 21257306.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 48 + ... + 6520.

It is an arithmetic number, because the mean of its divisors is an integer number (3104283).

Almost surely, 2^21257332 is an apocalyptic number.

It is an amenable number.

21257332 is a deficient number, since it is larger than the sum of its proper divisors (15994064).

21257332 is a wasteful number, since it uses less digits than its factorization.

21257332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7298 (or 7296 counting only the distinct ones).

The product of its digits is 2520, while the sum is 25.

The square root of 21257332 is about 4610.5674271178. The cubic root of 21257332 is about 277.0147654682.

The spelling of 21257332 in words is "twenty-one million, two hundred fifty-seven thousand, three hundred thirty-two".