1986116891 has 8 divisors (see below), whose sum is σ = 2167859568. Its totient is φ = 1804572000.

The previous prime is 1986116863. The next prime is 1986116903.

1986116891 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1986116891 - 2¹⁰ = 1986115867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1986116191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28040 + ... + 68981.

It is an arithmetic number, because the mean of its divisors is an integer number (270982446).

Almost surely, 2^1986116891 is an apocalyptic number.

1986116891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1986116891 is a deficient number, since it is larger than the sum of its proper divisors (181742677).

1986116891 is a wasteful number, since it uses less digits than its factorization.

1986116891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98893.

The product of its digits is 186624, while the sum is 50.

The square root of 1986116891 is about 44565.8713703659. The cubic root of 1986116891 is about 1256.9990080469. Note that the first 3 decimals are identical.

It can be divided in two parts, 198611 and 6891, that added together give a palindrome (205502).

The spelling of 1986116891 in words is "one billion, nine hundred eighty-six million, one hundred sixteen thousand, eight hundred ninety-one".