1331285257 has 2 divisors, whose sum is σ = 1331285258. Its totient is φ = 1331285256.

The previous prime is 1331285251. The next prime is 1331285261. The reversal of 1331285257 is 7525821331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 962798841 + 368486416 = 31029^2 + 19196^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331285257 is a prime.

It is not a weakly prime, because it can be changed into another prime (1331285251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665642628 + 665642629.

It is an arithmetic number, because the mean of its divisors is an integer number (665642629).

Almost surely, 2^1331285257 is an apocalyptic number.

It is an amenable number.

1331285257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331285257 is an equidigital number, since it uses as much as digits as its factorization.

1331285257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 50400, while the sum is 37.

The square root of 1331285257 is about 36486.7819490840. The cubic root of 1331285257 is about 1100.0785775823.

The spelling of 1331285257 in words is "one billion, three hundred thirty-one million, two hundred eighty-five thousand, two hundred fifty-seven".