1391321549 has 2 divisors, whose sum is σ = 1391321550. Its totient is φ = 1391321548.

The previous prime is 1391321513. The next prime is 1391321563. The reversal of 1391321549 is 9451231931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1074659524 + 316662025 = 32782^2 + 17795^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1391321549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1391321849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695660774 + 695660775.

It is an arithmetic number, because the mean of its divisors is an integer number (695660775).

Almost surely, 2^1391321549 is an apocalyptic number.

It is an amenable number.

1391321549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391321549 is an equidigital number, since it uses as much as digits as its factorization.

1391321549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29160, while the sum is 38.

The square root of 1391321549 is about 37300.4229064497. The cubic root of 1391321549 is about 1116.3726046608.

The spelling of 1391321549 in words is "one billion, three hundred ninety-one million, three hundred twenty-one thousand, five hundred forty-nine".