21253072 has 10 divisors (see below), whose sum is σ = 41177858. Its totient is φ = 10626528.

The previous prime is 21253033. The next prime is 21253093. The reversal of 21253072 is 27035212.

It can be written as a sum of positive squares in only one way, i.e., 14409616 + 6843456 = 3796^2 + 2616^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 664143 + ... + 664174.

Almost surely, 2^21253072 is an apocalyptic number.

It is an amenable number.

21253072 is a deficient number, since it is larger than the sum of its proper divisors (19924786).

21253072 is a wasteful number, since it uses less digits than its factorization.

21253072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1328325 (or 1328319 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21253072 is about 4610.1054217881. The cubic root of 21253072 is about 276.9962595124.

Adding to 21253072 its reverse (27035212), we get a palindrome (48288284).

The spelling of 21253072 in words is "twenty-one million, two hundred fifty-three thousand, seventy-two".