21100320120 has 64 divisors (see below), whose sum is σ = 69055597440. Its totient is φ = 5115228800.

The previous prime is 21100320119. The next prime is 21100320121. The reversal of 21100320120 is 2102300112.

It is an interprime number because it is at equal distance from previous prime (21100320119) and next prime (21100320121).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21100320096 and 21100320105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100320121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7991226 + ... + 7993865.

It is an arithmetic number, because the mean of its divisors is an integer number (1078993710).

Almost surely, 2^21100320120 is an apocalyptic number.

21100320120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100320120 is an abundant number, since it is smaller than the sum of its proper divisors (47955277320).

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

21100320120 is a wasteful number, since it uses less digits than its factorization.

21100320120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15985116 (or 15985112 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21100320120 its reverse (2102300112), we get a palindrome (23202620232).

The spelling of 21100320120 in words is "twenty-one billion, one hundred million, three hundred twenty thousand, one hundred twenty".