201231021 has 4 divisors (see below), whose sum is σ = 268308032. Its totient is φ = 134154012.

The previous prime is 201231007. The next prime is 201231061. The reversal of 201231021 is 120132102.

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 not a de Polignac number, because 201231021 - 2¹⁰ = 201229997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201230988 and 201231006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201231001) 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, 33538501 + ... + 33538506.

It is an arithmetic number, because the mean of its divisors is an integer number (67077008).

Almost surely, 2^201231021 is an apocalyptic number.

It is an amenable number.

201231021 is a deficient number, since it is larger than the sum of its proper divisors (67077011).

201231021 is an equidigital number, since it uses as much as digits as its factorization.

201231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67077010.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 201231021 is about 14185.5920214843. The cubic root of 201231021 is about 586.0009367207. Note that the first 3 decimals are identical.

Adding to 201231021 its reverse (120132102), we get a palindrome (321363123).

It can be divided in two parts, 2012 and 31021, that added together give a palindrome (33033).

The spelling of 201231021 in words is "two hundred one million, two hundred thirty-one thousand, twenty-one".