161901091 has 8 divisors (see below), whose sum is σ = 177274368. Its totient is φ = 146637000.

The previous prime is 161901073. The next prime is 161901097. The reversal of 161901091 is 190109161.

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 161901091 - 2⁵ = 161901059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161901097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24175 + ... + 30136.

It is an arithmetic number, because the mean of its divisors is an integer number (22159296).

Almost surely, 2^161901091 is an apocalyptic number.

161901091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161901091 is a deficient number, since it is larger than the sum of its proper divisors (15373277).

161901091 is a wasteful number, since it uses less digits than its factorization.

161901091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54593.

The product of its (nonzero) digits is 486, while the sum is 28.

The square root of 161901091 is about 12724.0359556235. The cubic root of 161901091 is about 545.0252110774.

The spelling of 161901091 in words is "one hundred sixty-one million, nine hundred one thousand, ninety-one".