21000023320 has 32 divisors (see below), whose sum is σ = 47848161600. Its totient is φ = 8293678848.

The previous prime is 21000023309. The next prime is 21000023333. The reversal of 21000023320 is 2332000012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21000023320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3319629 + ... + 3325948.

It is an arithmetic number, because the mean of its divisors is an integer number (1495255050).

Almost surely, 2^21000023320 is an apocalyptic number.

21000023320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000023320 is an abundant number, since it is smaller than the sum of its proper divisors (26848138280).

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

21000023320 is a wasteful number, since it uses less digits than its factorization.

21000023320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6645667 (or 6645663 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

Adding to 21000023320 its reverse (2332000012), we get a palindrome (23332023332).

The spelling of 21000023320 in words is "twenty-one billion, twenty-three thousand, three hundred twenty".