1987496891 has 2 divisors, whose sum is σ = 1987496892. Its totient is φ = 1987496890.

The previous prime is 1987496879. The next prime is 1987496897. The reversal of 1987496891 is 1986947891.

It is a strong prime.

It is an emirp because it is prime and its reverse (1986947891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1987496891 - 2³⁰ = 913755067 is a prime.

It is not a weakly prime, because it can be changed into another prime (1987496897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993748445 + 993748446.

It is an arithmetic number, because the mean of its divisors is an integer number (993748446).

Almost surely, 2^1987496891 is an apocalyptic number.

1987496891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987496891 is an equidigital number, since it uses as much as digits as its factorization.

1987496891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7838208, while the sum is 62.

The square root of 1987496891 is about 44581.3513814913. The cubic root of 1987496891 is about 1257.2900713160.

The spelling of 1987496891 in words is "one billion, nine hundred eighty-seven million, four hundred ninety-six thousand, eight hundred ninety-one".