21231013320 has 144 divisors (see below), whose sum is σ = 75844002780. Its totient is φ = 5146901760.

The previous prime is 21231013319. The next prime is 21231013333. The reversal of 21231013320 is 2331013212.

21231013320 is a `hidden beast` number, since 21 + 2 + 310 + 1 + 332 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17406580356 + 3824432964 = 131934^2 + 61842^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21231013293 and 21231013302.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 200139 + ... + 287258.

Almost surely, 2^21231013320 is an apocalyptic number.

21231013320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231013320 is an abundant number, since it is smaller than the sum of its proper divisors (54612989460).

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

21231013320 is a wasteful number, since it uses less digits than its factorization.

21231013320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 487436 (or 487418 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21231013320 its reverse (2331013212), we get a palindrome (23562026532).

The spelling of 21231013320 in words is "twenty-one billion, two hundred thirty-one million, thirteen thousand, three hundred twenty".