231403021 has 2 divisors, whose sum is σ = 231403022. Its totient is φ = 231403020.

The previous prime is 231403013. The next prime is 231403037. The reversal of 231403021 is 120304132.

It is a happy number.

It is an a-pointer prime, because the next prime (231403037) can be obtained adding 231403021 to its sum of digits (16).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 224700100 + 6702921 = 14990^2 + 2589^2 .

It is a cyclic number.

It is not a de Polignac number, because 231403021 - 2³ = 231403013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231402986 and 231403004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231403421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115701510 + 115701511.

It is an arithmetic number, because the mean of its divisors is an integer number (115701511).

Almost surely, 2^231403021 is an apocalyptic number.

It is an amenable number.

231403021 is a deficient number, since it is larger than the sum of its proper divisors (1).

231403021 is an equidigital number, since it uses as much as digits as its factorization.

231403021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 231403021 is about 15211.9367931897. The cubic root of 231403021 is about 613.9358697216.

Adding to 231403021 its reverse (120304132), we get a palindrome (351707153).

The spelling of 231403021 in words is "two hundred thirty-one million, four hundred three thousand, twenty-one".