161639059681 has 8 divisors (see below), whose sum is σ = 176439318624. Its totient is φ = 146856433920.

The previous prime is 161639059607. The next prime is 161639059697. The reversal of 161639059681 is 186950936161.

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 161639059681 - 2⁷ = 161639059553 is a prime.

It is a super-2 number, since 2×161639059681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161639059481) 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, 4389120 + ... + 4425793.

It is an arithmetic number, because the mean of its divisors is an integer number (22054914828).

Almost surely, 2^161639059681 is an apocalyptic number.

161639059681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161639059681 is a deficient number, since it is larger than the sum of its proper divisors (14800258943).

161639059681 is a wasteful number, since it uses less digits than its factorization.

161639059681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8816591.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The spelling of 161639059681 in words is "one hundred sixty-one billion, six hundred thirty-nine million, fifty-nine thousand, six hundred eighty-one".