161019391 has 8 divisors (see below), whose sum is σ = 177438800. Its totient is φ = 145176192.

The previous prime is 161019377. The next prime is 161019421. The reversal of 161019391 is 193910161.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161019391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161019311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 143466 + ... + 144583.

It is an arithmetic number, because the mean of its divisors is an integer number (22179850).

Almost surely, 2^161019391 is an apocalyptic number.

161019391 is a deficient number, since it is larger than the sum of its proper divisors (16419409).

161019391 is a wasteful number, since it uses less digits than its factorization.

161019391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288105.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 161019391 is about 12689.3416298877. The cubic root of 161019391 is about 544.0340221207.

The spelling of 161019391 in words is "one hundred sixty-one million, nineteen thousand, three hundred ninety-one".