3128891987 has 4 divisors (see below), whose sum is σ = 3369576000. Its totient is φ = 2888207976.

The previous prime is 3128891981. The next prime is 3128892001. The reversal of 3128891987 is 7891988213.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 3128891987 - 2¹² = 3128887891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3128891981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120341987 + ... + 120342012.

It is an arithmetic number, because the mean of its divisors is an integer number (842394000).

Almost surely, 2^3128891987 is an apocalyptic number.

3128891987 is a deficient number, since it is larger than the sum of its proper divisors (240684013).

3128891987 is a wasteful number, since it uses less digits than its factorization.

3128891987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240684012.

The product of its digits is 1741824, while the sum is 56.

The square root of 3128891987 is about 55936.4995955235. The cubic root of 3128891987 is about 1462.6155633912.

The spelling of 3128891987 in words is "three billion, one hundred twenty-eight million, eight hundred ninety-one thousand, nine hundred eighty-seven".