1988931987 has 24 divisors (see below), whose sum is σ = 3285574656. Its totient is φ = 1135750896.

The previous prime is 1988931979. The next prime is 1988931991. The reversal of 1988931987 is 7891398891.

1988931987 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1988931987 - 2³ = 1988931979 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (1988931907) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88648 + ... + 108794.

It is an arithmetic number, because the mean of its divisors is an integer number (136898944).

Almost surely, 2^1988931987 is an apocalyptic number.

1988931987 is a deficient number, since it is larger than the sum of its proper divisors (1296642669).

1988931987 is a wasteful number, since it uses less digits than its factorization.

1988931987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21727 (or 21724 counting only the distinct ones).

The product of its digits is 7838208, while the sum is 63.

The square root of 1988931987 is about 44597.4437271914. The cubic root of 1988931987 is about 1257.5926123086.

The spelling of 1988931987 in words is "one billion, nine hundred eighty-eight million, nine hundred thirty-one thousand, nine hundred eighty-seven".