1987856131 has 4 divisors (see below), whose sum is σ = 1988049672. Its totient is φ = 1987662592.

The previous prime is 1987856113. The next prime is 1987856219. The reversal of 1987856131 is 1316587891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1316587891 = 59 ⋅22315049.

It is a cyclic number.

It is not a de Polignac number, because 1987856131 - 2⁹ = 1987855619 is a prime.

It is a super-2 number, since 2×1987856131² = 7903143995108578322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987856831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80446 + ... + 102211.

It is an arithmetic number, because the mean of its divisors is an integer number (497012418).

Almost surely, 2^1987856131 is an apocalyptic number.

1987856131 is a deficient number, since it is larger than the sum of its proper divisors (193541).

1987856131 is a wasteful number, since it uses less digits than its factorization.

1987856131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193540.

The product of its digits is 362880, while the sum is 49.

The square root of 1987856131 is about 44585.3802383696. The cubic root of 1987856131 is about 1257.3658184660.

The spelling of 1987856131 in words is "one billion, nine hundred eighty-seven million, eight hundred fifty-six thousand, one hundred thirty-one".