1987156999 has 2 divisors, whose sum is σ = 1987157000. Its totient is φ = 1987156998.

The previous prime is 1987156991. The next prime is 1987157083. The reversal of 1987156999 is 9996517891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1987156999 - 2³ = 1987156991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1987156999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1987156991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993578499 + 993578500.

It is an arithmetic number, because the mean of its divisors is an integer number (993578500).

Almost surely, 2^1987156999 is an apocalyptic number.

1987156999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987156999 is an equidigital number, since it uses as much as digits as its factorization.

1987156999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11022480, while the sum is 64.

The square root of 1987156999 is about 44577.5391761367. The cubic root of 1987156999 is about 1257.2183953633.

The spelling of 1987156999 in words is "one billion, nine hundred eighty-seven million, one hundred fifty-six thousand, nine hundred ninety-nine".