2101010021 has 4 divisors (see below), whose sum is σ = 2292010944. Its totient is φ = 1910009100.

The previous prime is 2101010011. The next prime is 2101010069. The reversal of 2101010021 is 1200101012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2101010021 - 2¹⁰ = 2101008997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2101009990 and 2101010008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101010011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95500445 + ... + 95500466.

It is an arithmetic number, because the mean of its divisors is an integer number (573002736).

Almost surely, 2^2101010021 is an apocalyptic number.

It is an amenable number.

2101010021 is a deficient number, since it is larger than the sum of its proper divisors (191000923).

2101010021 is a wasteful number, since it uses less digits than its factorization.

2101010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191000922.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 2101010021 is about 45836.7758573833. The cubic root of 2101010021 is about 1280.7844355499.

Adding to 2101010021 its reverse (1200101012), we get a palindrome (3301111033).

Subtracting from 2101010021 its reverse (1200101012), we obtain a palindrome (900909009).

The spelling of 2101010021 in words is "two billion, one hundred one million, ten thousand, twenty-one".