161720779 has 8 divisors (see below), whose sum is σ = 186800688. Its totient is φ = 138370560.

The previous prime is 161720777. The next prime is 161720789. The reversal of 161720779 is 977027161.

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 161720779 - 2¹ = 161720777 is a prime.

It is a super-2 number, since 2×161720779² = 52307220720733682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161720771) 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, 432222 + ... + 432595.

It is an arithmetic number, because the mean of its divisors is an integer number (23350086).

Almost surely, 2^161720779 is an apocalyptic number.

161720779 is a deficient number, since it is larger than the sum of its proper divisors (25079909).

161720779 is a wasteful number, since it uses less digits than its factorization.

161720779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864845.

The product of its (nonzero) digits is 37044, while the sum is 40.

The square root of 161720779 is about 12716.9484940374. The cubic root of 161720779 is about 544.8228012991.

The spelling of 161720779 in words is "one hundred sixty-one million, seven hundred twenty thousand, seven hundred seventy-nine".