1990878687 has 48 divisors (see below), whose sum is σ = 3553984512. Its totient is φ = 1047916800.

The previous prime is 1990878679. The next prime is 1990878707. The reversal of 1990878687 is 7868780991.

It is not a de Polignac number, because 1990878687 - 2³ = 1990878679 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990878667) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 30562 + ... + 70112.

It is an arithmetic number, because the mean of its divisors is an integer number (74041344).

Almost surely, 2^1990878687 is an apocalyptic number.

1990878687 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

1990878687 is a deficient number, since it is larger than the sum of its proper divisors (1563105825).

1990878687 is a wasteful number, since it uses less digits than its factorization.

1990878687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39628 (or 39625 counting only the distinct ones).

The product of its (nonzero) digits is 12192768, while the sum is 63.

The square root of 1990878687 is about 44619.2636313062. The cubic root of 1990878687 is about 1258.0027750265.

The spelling of 1990878687 in words is "one billion, nine hundred ninety million, eight hundred seventy-eight thousand, six hundred eighty-seven".