161865705680 has 40 divisors (see below), whose sum is σ = 430100305152. Its totient is φ = 55496813184.

The previous prime is 161865705629. The next prime is 161865705689. The reversal of 161865705680 is 86507568161.

161865705680 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161865705689) 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, 144522392 + ... + 144523511.

Almost surely, 2^161865705680 is an apocalyptic number.

161865705680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161865705680 is an abundant number, since it is smaller than the sum of its proper divisors (268234599472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161865705680 is a wasteful number, since it uses less digits than its factorization.

161865705680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289045923 (or 289045917 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 53.

The spelling of 161865705680 in words is "one hundred sixty-one billion, eight hundred sixty-five million, seven hundred five thousand, six hundred eighty".