231933781 has 2 divisors, whose sum is σ = 231933782. Its totient is φ = 231933780.

The previous prime is 231933769. The next prime is 231933791. The reversal of 231933781 is 187339132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193071025 + 38862756 = 13895^2 + 6234^2 .

It is a cyclic number.

It is not a de Polignac number, because 231933781 - 2⁵ = 231933749 is a prime.

It is a super-2 number, since 2×231933781² = 107586557537911922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 231933781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231933721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115966890 + 115966891.

It is an arithmetic number, because the mean of its divisors is an integer number (115966891).

Almost surely, 2^231933781 is an apocalyptic number.

It is an amenable number.

231933781 is a deficient number, since it is larger than the sum of its proper divisors (1).

231933781 is an equidigital number, since it uses as much as digits as its factorization.

231933781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The square root of 231933781 is about 15229.3723114251. The cubic root of 231933781 is about 614.4048981523.

It can be divided in two parts, 2319 and 33781, that added together give a square (36100 = 190²).

The spelling of 231933781 in words is "two hundred thirty-one million, nine hundred thirty-three thousand, seven hundred eighty-one".