2120001000021 has 12 divisors (see below), whose sum is σ = 3062254272480. Its totient is φ = 1413319874280.

The previous prime is 2120000999959. The next prime is 2120001000059. The reversal of 2120001000021 is 1200001000212.

It is not a de Polignac number, because 2120001000021 - 2⁶ = 2120000999957 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 2120000999967 and 2120001000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120001040021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 182391 + ... + 2067188.

It is an arithmetic number, because the mean of its divisors is an integer number (255187856040).

Almost surely, 2^{2120001000021} is an apocalyptic number.

It is an amenable number.

2120001000021 is a deficient number, since it is larger than the sum of its proper divisors (942253272459).

2120001000021 is a wasteful number, since it uses less digits than its factorization.

2120001000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2354296 (or 2354293 counting only the distinct ones).

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

Adding to 2120001000021 its reverse (1200001000212), we get a palindrome (3320002000233).

The spelling of 2120001000021 in words is "two trillion, one hundred twenty billion, one million, twenty-one", and thus it is an aban number.