161866188965664 has 576 divisors, whose sum is σ = 524122892092800. Its totient is φ = 47074043068416.

The previous prime is 161866188965641. The next prime is 161866188965693. The reversal of 161866188965664 is 466569881668161.

It is a Smith number, since the sum of its digits (81) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1838947447 + ... + 1839035465.

It is an arithmetic number, because the mean of its divisors is an integer number (909935576550).

Almost surely, 2^{161866188965664} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161866188965664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (262061446046400).

161866188965664 is an abundant number, since it is smaller than the sum of its proper divisors (362256703127136).

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

161866188965664 is a wasteful number, since it uses less digits than its factorization.

161866188965664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88497 (or 88486 counting only the distinct ones).

The product of its digits is 4299816960, while the sum is 81.

The spelling of 161866188965664 in words is "one hundred sixty-one trillion, eight hundred sixty-six billion, one hundred eighty-eight million, nine hundred sixty-five thousand, six hundred sixty-four".