2120100021 has 16 divisors (see below), whose sum is σ = 3382496320. Its totient is φ = 1304676720.

The previous prime is 2120099999. The next prime is 2120100023. The reversal of 2120100021 is 1200010212.

It is not a de Polignac number, because 2120100021 - 2⁷ = 2120099893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2120099976 and 2120100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120100023) 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, 3019735 + ... + 3020436.

It is an arithmetic number, because the mean of its divisors is an integer number (211406020).

Almost surely, 2^2120100021 is an apocalyptic number.

It is an amenable number.

2120100021 is a deficient number, since it is larger than the sum of its proper divisors (1262396299).

2120100021 is a wasteful number, since it uses less digits than its factorization.

2120100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6040193 (or 6040187 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 2120100021 is about 46044.5438787268. The cubic root of 2120100021 is about 1284.6518602474.

Adding to 2120100021 its reverse (1200010212), we get a palindrome (3320110233).

The spelling of 2120100021 in words is "two billion, one hundred twenty million, one hundred thousand, twenty-one".