1987998040 has 64 divisors (see below), whose sum is σ = 5121480960. Its totient is φ = 680334720.

The previous prime is 1987998013. The next prime is 1987998109. The reversal of 1987998040 is 408997891.

1987998040 is a nontrivial binomial coefficient, being equal to C(63056, 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 151335 + ... + 163945.

It is an arithmetic number, because the mean of its divisors is an integer number (80023140).

Almost surely, 2^1987998040 is an apocalyptic number.

1987998040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1987998040 is the 63055-th triangular number and also the 31528-th hexagonal number.

1987998040 is the 21019-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1987998040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2560740480).

1987998040 is an abundant number, since it is smaller than the sum of its proper divisors (3133482920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1987998040 is a wasteful number, since it uses less digits than its factorization.

1987998040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13192 (or 13188 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 55.

The square root of 1987998040 is about 44586.9716397066. The cubic root of 1987998040 is about 1257.3957380155.

The spelling of 1987998040 in words is "one billion, nine hundred eighty-seven million, nine hundred ninety-eight thousand, forty".