21020000120 has 64 divisors (see below), whose sum is σ = 55795046400. Its totient is φ = 6974375040.

The previous prime is 21020000119. The next prime is 21020000123. The reversal of 21020000120 is 2100002012.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a junction number, because it is equal to n+sod(n) for n = 21020000098 and 21020000107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020000123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1202150 + ... + 1219509.

It is an arithmetic number, because the mean of its divisors is an integer number (871797600).

Almost surely, 2^21020000120 is an apocalyptic number.

21020000120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020000120 is an abundant number, since it is smaller than the sum of its proper divisors (34775046280).

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

21020000120 is a wasteful number, since it uses less digits than its factorization.

21020000120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2421708 (or 2421704 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

Adding to 21020000120 its reverse (2100002012), we get a palindrome (23120002132).

The spelling of 21020000120 in words is "twenty-one billion, twenty million, one hundred twenty", and thus it is an aban number.