1991188485 has 96 divisors (see below), whose sum is σ = 4164870528. Its totient is φ = 866972160.

The previous prime is 1991188447. The next prime is 1991188531. The reversal of 1991188485 is 5848811991.

It is not a de Polignac number, because 1991188485 - 2¹⁴ = 1991172101 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 233914 + ... + 242276.

It is an arithmetic number, because the mean of its divisors is an integer number (43384068).

Almost surely, 2^1991188485 is an apocalyptic number.

1991188485 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1991188485 is an abundant number, since it is smaller than the sum of its proper divisors (2173682043).

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

1991188485 is a wasteful number, since it uses less digits than its factorization.

1991188485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8435 (or 8432 counting only the distinct ones).

The product of its digits is 829440, while the sum is 54.

The square root of 1991188485 is about 44622.7350685724. The cubic root of 1991188485 is about 1258.0680236916.

The spelling of 1991188485 in words is "one billion, nine hundred ninety-one million, one hundred eighty-eight thousand, four hundred eighty-five".