202131223421 has 4 divisors (see below), whose sum is σ = 202331552700. Its totient is φ = 201930894144.

The previous prime is 202131223363. The next prime is 202131223477. The reversal of 202131223421 is 124322131202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39491625625 + 162639597796 = 198725^2 + 403286^2 .

It is a cyclic number.

It is not a de Polignac number, because 202131223421 - 2²⁶ = 202064114557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (202131223321) 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, 100163126 + ... + 100165143.

It is an arithmetic number, because the mean of its divisors is an integer number (50582888175).

Almost surely, 2^202131223421 is an apocalyptic number.

It is an amenable number.

202131223421 is a deficient number, since it is larger than the sum of its proper divisors (200329279).

202131223421 is a wasteful number, since it uses less digits than its factorization.

202131223421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200329278.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 202131223421 its reverse (124322131202), we get a palindrome (326453354623).

The spelling of 202131223421 in words is "two hundred two billion, one hundred thirty-one million, two hundred twenty-three thousand, four hundred twenty-one".