21421323020 has 24 divisors (see below), whose sum is σ = 46435901568. Its totient is φ = 8292124800.

The previous prime is 21421323017. The next prime is 21421323037. The reversal of 21421323020 is 2032312412.

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 = 21421322983 and 21421323001.

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, 17274641 + ... + 17275880.

It is an arithmetic number, because the mean of its divisors is an integer number (1934829232).

Almost surely, 2^21421323020 is an apocalyptic number.

21421323020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421323020 is an abundant number, since it is smaller than the sum of its proper divisors (25014578548).

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

21421323020 is a wasteful number, since it uses less digits than its factorization.

21421323020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34550561 (or 34550559 counting only the distinct ones).

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

Adding to 21421323020 its reverse (2032312412), we get a palindrome (23453635432).

The spelling of 21421323020 in words is "twenty-one billion, four hundred twenty-one million, three hundred twenty-three thousand, twenty".