161211779907 has 8 divisors (see below), whose sum is σ = 221882880000. Its totient is φ = 104007599880.

The previous prime is 161211779887. The next prime is 161211779959. The reversal of 161211779907 is 709977112161.

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

It is not a de Polignac number, because 161211779907 - 2²⁷ = 161077562179 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161211779907.

It is not an unprimeable number, because it can be changed into a prime (161211777907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 866729907 + ... + 866730092.

It is an arithmetic number, because the mean of its divisors is an integer number (27735360000).

Almost surely, 2^161211779907 is an apocalyptic number.

161211779907 is a deficient number, since it is larger than the sum of its proper divisors (60671100093).

161211779907 is a wasteful number, since it uses less digits than its factorization.

161211779907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1733460033.

The product of its (nonzero) digits is 333396, while the sum is 51.

The spelling of 161211779907 in words is "one hundred sixty-one billion, two hundred eleven million, seven hundred seventy-nine thousand, nine hundred seven".