1987157081 has 16 divisors (see below), whose sum is σ = 2589600384. Its totient is φ = 1479769344.

The previous prime is 1987156999. The next prime is 1987157083. The reversal of 1987157081 is 1807517891.

It is a cyclic number.

It is not a de Polignac number, because 1987157081 - 2¹⁰ = 1987156057 is a prime.

It is a super-2 number, since 2×1987157081² = 7897586529136881122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1987157083) 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 in 15 ways as a sum of consecutive naturals, for example, 640715 + ... + 643808.

It is an arithmetic number, because the mean of its divisors is an integer number (161850024).

Almost surely, 2^1987157081 is an apocalyptic number.

It is an amenable number.

1987157081 is a deficient number, since it is larger than the sum of its proper divisors (602443303).

1987157081 is a wasteful number, since it uses less digits than its factorization.

1987157081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1284560.

The product of its (nonzero) digits is 141120, while the sum is 47.

The square root of 1987157081 is about 44577.5400958824. The cubic root of 1987157081 is about 1257.2184126563.

The spelling of 1987157081 in words is "one billion, nine hundred eighty-seven million, one hundred fifty-seven thousand, eighty-one".