21240253832 has 108 divisors (see below), whose sum is σ = 49326968655. Its totient is φ = 8547710976.

The previous prime is 21240253829. The next prime is 21240253873. The reversal of 21240253832 is 23835204212.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 5 ways, for example, as 7512382276 + 13727871556 = 86674^2 + 117166^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=103054.

It is a super-2 number, since 2×21240253832² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 49053488 + ... + 49053920.

Almost surely, 2^21240253832 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21240253832

21240253832 is an abundant number, since it is smaller than the sum of its proper divisors (28086714823).

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

21240253832 is an equidigital number, since it uses as much as digits as its factorization.

21240253832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920 (or 459 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

Multiplying 21240253832 by its sum of digits (32), we get a square (679688122624 = 824432²).

The spelling of 21240253832 in words is "twenty-one billion, two hundred forty million, two hundred fifty-three thousand, eight hundred thirty-two".