21023421320 has 32 divisors (see below), whose sum is σ = 51602944320. Its totient is φ = 7644880320.

The previous prime is 21023421301. The next prime is 21023421347. The reversal of 21023421320 is 2312432012.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21023421292 and 21023421301.

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, 23889812 + ... + 23890691.

It is an arithmetic number, because the mean of its divisors is an integer number (1612592010).

Almost surely, 2^21023421320 is an apocalyptic number.

21023421320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21023421320 is an abundant number, since it is smaller than the sum of its proper divisors (30579523000).

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

21023421320 is a wasteful number, since it uses less digits than its factorization.

21023421320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47780525 (or 47780521 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21023421320 its reverse (2312432012), we get a palindrome (23335853332).

The spelling of 21023421320 in words is "twenty-one billion, twenty-three million, four hundred twenty-one thousand, three hundred twenty".