2131021021 has 4 divisors (see below), whose sum is σ = 2131115932. Its totient is φ = 2130926112.

The previous prime is 2131020977. The next prime is 2131021049. The reversal of 2131021021 is 1201201312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 656076996 + 1474944025 = 25614^2 + 38405^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131021021 - 2⁹ = 2131020509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2131020992 and 2131021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131021121) 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, 7231 + ... + 65683.

It is an arithmetic number, because the mean of its divisors is an integer number (532778983).

Almost surely, 2^2131021021 is an apocalyptic number.

It is an amenable number.

2131021021 is a deficient number, since it is larger than the sum of its proper divisors (94911).

2131021021 is an equidigital number, since it uses as much as digits as its factorization.

2131021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94910.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 2131021021 is about 46162.9832333223. The cubic root of 2131021021 is about 1286.8539044529.

Adding to 2131021021 its reverse (1201201312), we get a palindrome (3332222333).

The spelling of 2131021021 in words is "two billion, one hundred thirty-one million, twenty-one thousand, twenty-one".