1991182986 has 40 divisors (see below), whose sum is σ = 4804939524. Its totient is φ = 612671040.

The previous prime is 1991182981. The next prime is 1991182993. The reversal of 1991182986 is 6892811991.

It can be written as a sum of positive squares in 2 ways, for example, as 1885730625 + 105452361 = 43425^2 + 10269^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1991182981) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 470635 + ... + 474846.

Almost surely, 2^1991182986 is an apocalyptic number.

1991182986 is an abundant number, since it is smaller than the sum of its proper divisors (2813756538).

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

1991182986 is a wasteful number, since it uses less digits than its factorization.

1991182986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 945508 (or 945499 counting only the distinct ones).

The product of its digits is 559872, while the sum is 54.

The square root of 1991182986 is about 44622.6734519571. The cubic root of 1991182986 is about 1258.0668655688.

The spelling of 1991182986 in words is "one billion, nine hundred ninety-one million, one hundred eighty-two thousand, nine hundred eighty-six".