21310023220 has 12 divisors (see below), whose sum is σ = 44751048804. Its totient is φ = 8524009280.

The previous prime is 21310023169. The next prime is 21310023221. The reversal of 21310023220 is 2232001312.

It can be written as a sum of positive squares in 2 ways, for example, as 9603216016 + 11706807204 = 97996^2 + 108198^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21310023194 and 21310023203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310023221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532750561 + ... + 532750600.

It is an arithmetic number, because the mean of its divisors is an integer number (3729254067).

Almost surely, 2^21310023220 is an apocalyptic number.

21310023220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21310023220 is an abundant number, since it is smaller than the sum of its proper divisors (23441025584).

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

21310023220 is a wasteful number, since it uses less digits than its factorization.

21310023220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1065501170 (or 1065501168 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21310023220 its reverse (2232001312), we get a palindrome (23542024532).

The spelling of 21310023220 in words is "twenty-one billion, three hundred ten million, twenty-three thousand, two hundred twenty".