21004321020 has 96 divisors (see below), whose sum is σ = 61936358400. Its totient is φ = 5303879424.

The previous prime is 21004321007. The next prime is 21004321067. The reversal of 21004321020 is 2012340012.

It is a super-2 number, since 2×21004321020² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4647802 + ... + 4652318.

It is an arithmetic number, because the mean of its divisors is an integer number (645170400).

Almost surely, 2^21004321020 is an apocalyptic number.

21004321020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004321020 is an abundant number, since it is smaller than the sum of its proper divisors (40932037380).

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

21004321020 is a wasteful number, since it uses less digits than its factorization.

21004321020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8627 (or 8625 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21004321020 its reverse (2012340012), we get a palindrome (23016661032).

The spelling of 21004321020 in words is "twenty-one billion, four million, three hundred twenty-one thousand, twenty".