2100020010021 has 24 divisors (see below), whose sum is σ = 3224969220096. Its totient is φ = 1313876335200.

The previous prime is 2100020010019. The next prime is 2100020010037. The reversal of 2100020010021 is 1200100200012.

It is not a de Polignac number, because 2100020010021 - 2¹ = 2100020010019 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 = 2100020009985 and 2100020010012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100020010421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 95696805 + ... + 95718746.

It is an arithmetic number, because the mean of its divisors is an integer number (134373717504).

Almost surely, 2^{2100020010021} is an apocalyptic number.

It is an amenable number.

2100020010021 is a deficient number, since it is larger than the sum of its proper divisors (1124949210075).

2100020010021 is a wasteful number, since it uses less digits than its factorization.

2100020010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191415633 (or 191415630 counting only the distinct ones).

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

Adding to 2100020010021 its reverse (1200100200012), we get a palindrome (3300120210033).

The spelling of 2100020010021 in words is "two trillion, one hundred billion, twenty million, ten thousand, twenty-one".