161777218507 has 12 divisors (see below), whose sum is σ = 179325198576. Its totient is φ = 145640865920.

The previous prime is 161777218429. The next prime is 161777218511. The reversal of 161777218507 is 705812777161.

It is not a de Polignac number, because 161777218507 - 2¹¹ = 161777216459 is a prime.

It is a super-3 number, since 3×161777218507³ (a number of 35 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161777215507) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12162544 + ... + 12175837.

It is an arithmetic number, because the mean of its divisors is an integer number (14943766548).

Almost surely, 2^161777218507 is an apocalyptic number.

161777218507 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

161777218507 is a deficient number, since it is larger than the sum of its proper divisors (17547980069).

161777218507 is a wasteful number, since it uses less digits than its factorization.

161777218507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24338438 (or 24338421 counting only the distinct ones).

The product of its (nonzero) digits is 1152480, while the sum is 52.

The spelling of 161777218507 in words is "one hundred sixty-one billion, seven hundred seventy-seven million, two hundred eighteen thousand, five hundred seven".