1231808257 has 4 divisors (see below), whose sum is σ = 1232879616. Its totient is φ = 1230736900.

The previous prime is 1231808251. The next prime is 1231808261. The reversal of 1231808257 is 7528081321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1231808257 - 2²³ = 1223419649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231808251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 533953 + ... + 536254.

It is an arithmetic number, because the mean of its divisors is an integer number (308219904).

Almost surely, 2^1231808257 is an apocalyptic number.

It is an amenable number.

1231808257 is a deficient number, since it is larger than the sum of its proper divisors (1071359).

1231808257 is a wasteful number, since it uses less digits than its factorization.

1231808257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1071358.

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 1231808257 is about 35097.1260504332. The cubic root of 1231808257 is about 1071.9660644122.

Adding to 1231808257 its reverse (7528081321), we get a palindrome (8759889578).

The spelling of 1231808257 in words is "one billion, two hundred thirty-one million, eight hundred eight thousand, two hundred fifty-seven".