1991290171 has 8 divisors (see below), whose sum is σ = 2145525984. Its totient is φ = 1837205760.

The previous prime is 1991290141. The next prime is 1991290199. The reversal of 1991290171 is 1710921991.

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

It is a de Polignac number, because none of the positive numbers 2^k-1991290171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991290111) 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, 9751 + ... + 63856.

It is an arithmetic number, because the mean of its divisors is an integer number (268190748).

Almost surely, 2^1991290171 is an apocalyptic number.

1991290171 is a deficient number, since it is larger than the sum of its proper divisors (154235813).

1991290171 is a wasteful number, since it uses less digits than its factorization.

1991290171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75701.

The product of its (nonzero) digits is 10206, while the sum is 40.

The square root of 1991290171 is about 44623.8744507915. The cubic root of 1991290171 is about 1258.0894389968.

The spelling of 1991290171 in words is "one billion, nine hundred ninety-one million, two hundred ninety thousand, one hundred seventy-one".