1331262391 has 2 divisors, whose sum is σ = 1331262392. Its totient is φ = 1331262390.

The previous prime is 1331262347. The next prime is 1331262409. The reversal of 1331262391 is 1932621331.

It is a strong prime.

It is an emirp because it is prime and its reverse (1932621331) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331262391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1331262301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665631195 + 665631196.

It is an arithmetic number, because the mean of its divisors is an integer number (665631196).

Almost surely, 2^1331262391 is an apocalyptic number.

1331262391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331262391 is an equidigital number, since it uses as much as digits as its factorization.

1331262391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 31.

The square root of 1331262391 is about 36486.4686013870. The cubic root of 1331262391 is about 1100.0722792726.

The spelling of 1331262391 in words is "one billion, three hundred thirty-one million, two hundred sixty-two thousand, three hundred ninety-one".