1331388657 has 20 divisors (see below), whose sum is σ = 1989854196. Its totient is φ = 887150880.

The previous prime is 1331388581. The next prime is 1331388679. The reversal of 1331388657 is 7568831331.

It can be written as a sum of positive squares in 2 ways, for example, as 314033841 + 1017354816 = 17721^2 + 31896^2 .

It is not a de Polignac number, because 1331388657 - 2⁷ = 1331388529 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1331388857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 285807 + ... + 290427.

Almost surely, 2^1331388657 is an apocalyptic number.

It is an amenable number.

1331388657 is a deficient number, since it is larger than the sum of its proper divisors (658465539).

1331388657 is an equidigital number, since it uses as much as digits as its factorization.

1331388657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190 (or 8181 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 1331388657 is about 36488.1988730603. The cubic root of 1331388657 is about 1100.1070576243.

The spelling of 1331388657 in words is "one billion, three hundred thirty-one million, three hundred eighty-eight thousand, six hundred fifty-seven".