231401221 has 2 divisors, whose sum is σ = 231401222. Its totient is φ = 231401220.

The previous prime is 231401197. The next prime is 231401231. The reversal of 231401221 is 122104132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 231344100 + 57121 = 15210^2 + 239^2 .

It is a cyclic number.

It is not a de Polignac number, because 231401221 - 2²¹ = 229304069 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231401195 and 231401204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231401231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115700610 + 115700611.

It is an arithmetic number, because the mean of its divisors is an integer number (115700611).

Almost surely, 2^231401221 is an apocalyptic number.

It is an amenable number.

231401221 is a deficient number, since it is larger than the sum of its proper divisors (1).

231401221 is an equidigital number, since it uses as much as digits as its factorization.

231401221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 231401221 is about 15211.8776290108. The cubic root of 231401221 is about 613.9342778561.

Adding to 231401221 its reverse (122104132), we get a palindrome (353505353).

The spelling of 231401221 in words is "two hundred thirty-one million, four hundred one thousand, two hundred twenty-one".