161936198391 has 8 divisors (see below), whose sum is σ = 235543561344. Its totient is φ = 98143150520.

The previous prime is 161936198329. The next prime is 161936198399. The reversal of 161936198391 is 193891639161.

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

It is a cyclic number.

It is not a de Polignac number, because 161936198391 - 2³³ = 153346263799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161936198399) 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, 2453578731 + ... + 2453578796.

It is an arithmetic number, because the mean of its divisors is an integer number (29442945168).

Almost surely, 2^161936198391 is an apocalyptic number.

161936198391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161936198391 is a deficient number, since it is larger than the sum of its proper divisors (73607362953).

161936198391 is a wasteful number, since it uses less digits than its factorization.

161936198391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4907157541.

The product of its digits is 1889568, while the sum is 57.

The spelling of 161936198391 in words is "one hundred sixty-one billion, nine hundred thirty-six million, one hundred ninety-eight thousand, three hundred ninety-one".