1991188486 has 32 divisors (see below), whose sum is σ = 3595749120. Its totient is φ = 807861600.

The previous prime is 1991188447. The next prime is 1991188531. The reversal of 1991188486 is 6848811991.

It is a happy number.

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, 725076 + ... + 727816.

It is an arithmetic number, because the mean of its divisors is an integer number (112367160).

Almost surely, 2^1991188486 is an apocalyptic number.

1991188486 is a deficient number, since it is larger than the sum of its proper divisors (1604560634).

1991188486 is a wasteful number, since it uses less digits than its factorization.

1991188486 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5500.

The product of its digits is 995328, while the sum is 55.

The square root of 1991188486 is about 44622.7350797774. The cubic root of 1991188486 is about 1258.0680239022.

The spelling of 1991188486 in words is "one billion, nine hundred ninety-one million, one hundred eighty-eight thousand, four hundred eighty-six".