2100020001021 has 12 divisors (see below), whose sum is σ = 3034361065372. Its totient is φ = 1399552330176.

The previous prime is 2100020000989. The next prime is 2100020001031. The reversal of 2100020001021 is 1201000200012.

It can be written as a sum of positive squares in 2 ways, for example, as 899483424921 + 1200536576100 = 948411^2 + 1095690^2 .

It is not a de Polignac number, because 2100020001021 - 2⁵ = 2100020000989 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 junction number, because it is equal to n+sod(n) for n = 2100020000994 and 2100020001012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100020001031) 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, 38388136 + ... + 38442801.

Almost surely, 2^{2100020001021} is an apocalyptic number.

It is an amenable number.

2100020001021 is a deficient number, since it is larger than the sum of its proper divisors (934341064351).

2100020001021 is a wasteful number, since it uses less digits than its factorization.

2100020001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76833980 (or 76833977 counting only the distinct ones).

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

Adding to 2100020001021 its reverse (1201000200012), we get a palindrome (3301020201033).

The spelling of 2100020001021 in words is "two trillion, one hundred billion, twenty million, one thousand, twenty-one".