231521401 has 2 divisors, whose sum is σ = 231521402. Its totient is φ = 231521400.

The previous prime is 231521393. The next prime is 231521431. The reversal of 231521401 is 104125132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 194323600 + 37197801 = 13940^2 + 6099^2 .

It is a cyclic number.

It is not a de Polignac number, because 231521401 - 2³ = 231521393 is a prime.

It is not a weakly prime, because it can be changed into another prime (231521431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115760700 + 115760701.

It is an arithmetic number, because the mean of its divisors is an integer number (115760701).

Almost surely, 2^231521401 is an apocalyptic number.

It is an amenable number.

231521401 is a deficient number, since it is larger than the sum of its proper divisors (1).

231521401 is an equidigital number, since it uses as much as digits as its factorization.

231521401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 231521401 is about 15215.8273189465. The cubic root of 231521401 is about 614.0405432879.

Adding to 231521401 its reverse (104125132), we get a palindrome (335646533).

It can be divided in two parts, 2315 and 21401, that added together give a square (23716 = 154²).

The spelling of 231521401 in words is "two hundred thirty-one million, five hundred twenty-one thousand, four hundred one".