1581116731 has 2 divisors, whose sum is σ = 1581116732. Its totient is φ = 1581116730.

The previous prime is 1581116687. The next prime is 1581116741. The reversal of 1581116731 is 1376111851.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1376111851) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1581116731 is a prime.

It is a super-2 number, since 2×1581116731² = 4999860234096252722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1581116741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 790558365 + 790558366.

It is an arithmetic number, because the mean of its divisors is an integer number (790558366).

Almost surely, 2^1581116731 is an apocalyptic number.

1581116731 is a deficient number, since it is larger than the sum of its proper divisors (1).

1581116731 is an equidigital number, since it uses as much as digits as its factorization.

1581116731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 34.

The square root of 1581116731 is about 39763.2585561093. The cubic root of 1581116731 is about 1164.9876231439.

The spelling of 1581116731 in words is "one billion, five hundred eighty-one million, one hundred sixteen thousand, seven hundred thirty-one".