1331257643 has 2 divisors, whose sum is σ = 1331257644. Its totient is φ = 1331257642.

The previous prime is 1331257621. The next prime is 1331257691. The reversal of 1331257643 is 3467521331.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1331257643 - 2²⁶ = 1264148779 is a prime.

It is a Sophie Germain prime.

It is a zygodrome in base 7.

It is not a weakly prime, because it can be changed into another prime (1331257243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665628821 + 665628822.

It is an arithmetic number, because the mean of its divisors is an integer number (665628822).

Almost surely, 2^1331257643 is an apocalyptic number.

1331257643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331257643 is an equidigital number, since it uses as much as digits as its factorization.

1331257643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 35.

The square root of 1331257643 is about 36486.4035361119. The cubic root of 1331257643 is about 1100.0709714539.

Adding to 1331257643 its reverse (3467521331), we get a palindrome (4798778974).

The spelling of 1331257643 in words is "one billion, three hundred thirty-one million, two hundred fifty-seven thousand, six hundred forty-three".