231442639 has 2 divisors, whose sum is σ = 231442640. Its totient is φ = 231442638.

The previous prime is 231442637. The next prime is 231442657. The reversal of 231442639 is 936244132.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231442639 - 2¹ = 231442637 is a prime.

Together with 231442637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231442637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115721319 + 115721320.

It is an arithmetic number, because the mean of its divisors is an integer number (115721320).

Almost surely, 2^231442639 is an apocalyptic number.

231442639 is a deficient number, since it is larger than the sum of its proper divisors (1).

231442639 is an equidigital number, since it uses as much as digits as its factorization.

231442639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 34.

The square root of 231442639 is about 15213.2389385035. The cubic root of 231442639 is about 613.9709045902.

It can be divided in two parts, 23144 and 2639, that multiplied together give a palindrome (61077016).

The spelling of 231442639 in words is "two hundred thirty-one million, four hundred forty-two thousand, six hundred thirty-nine".