161906961840 has 240 divisors, whose sum is σ = 544411396512. Its totient is φ = 39786479616.

The previous prime is 161906961823. The next prime is 161906961841. The reversal of 161906961840 is 48169609161.

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (161906961841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 26482624 + ... + 26488736.

Almost surely, 2^161906961840 is an apocalyptic number.

161906961840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161906961840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (272205698256).

161906961840 is an abundant number, since it is smaller than the sum of its proper divisors (382504434672).

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

161906961840 is a wasteful number, since it uses less digits than its factorization.

161906961840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6808 (or 6789 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 51.

The spelling of 161906961840 in words is "one hundred sixty-one billion, nine hundred six million, nine hundred sixty-one thousand, eight hundred forty".