201231312021 has 24 divisors (see below), whose sum is σ = 297850100184. Its totient is φ = 130841187840.

The previous prime is 201231312013. The next prime is 201231312031. The reversal of 201231312021 is 120213132102.

201231312021 is a `hidden beast` number, since 201 + 231 + 31 + 202 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 59907947121 + 141323364900 = 244761^2 + 375930^2 .

It is not a de Polignac number, because 201231312021 - 2³ = 201231312013 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 201231311985 and 201231312003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201231312031) 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, 1118115 + ... + 1285551.

It is an arithmetic number, because the mean of its divisors is an integer number (12410420841).

Almost surely, 2^201231312021 is an apocalyptic number.

It is an amenable number.

201231312021 is a deficient number, since it is larger than the sum of its proper divisors (96618788163).

201231312021 is a wasteful number, since it uses less digits than its factorization.

201231312021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170741 (or 170738 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 201231312021 its reverse (120213132102), we get a palindrome (321444444123).

The spelling of 201231312021 in words is "two hundred one billion, two hundred thirty-one million, three hundred twelve thousand, twenty-one".