1491757987 has 2 divisors, whose sum is σ = 1491757988. Its totient is φ = 1491757986.

The previous prime is 1491757931. The next prime is 1491758011. The reversal of 1491757987 is 7897571941.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1491757987 is a prime.

It is not a weakly prime, because it can be changed into another prime (1491754987) 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 as a sum of consecutive naturals, namely, 745878993 + 745878994.

It is an arithmetic number, because the mean of its divisors is an integer number (745878994).

Almost surely, 2^1491757987 is an apocalyptic number.

1491757987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491757987 is an equidigital number, since it uses as much as digits as its factorization.

1491757987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4445280, while the sum is 58.

The square root of 1491757987 is about 38623.2829650717. The cubic root of 1491757987 is about 1142.6137796850.

The spelling of 1491757987 in words is "one billion, four hundred ninety-one million, seven hundred fifty-seven thousand, nine hundred eighty-seven".