161198978688 has 1280 divisors, whose sum is σ = 595022630400. Its totient is φ = 42732748800.

The previous prime is 161198978617. The next prime is 161198978711. The reversal of 161198978688 is 886879891161.

It is a super-2 number, since 2×161198978688² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 2642606178 + ... + 2642606238.

It is an arithmetic number, because the mean of its divisors is an integer number (464861430).

Almost surely, 2^161198978688 is an apocalyptic number.

161198978688 is a gapful number since it is divisible by the number (18) 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 161198978688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (297511315200).

161198978688 is an abundant number, since it is smaller than the sum of its proper divisors (433823651712).

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

161198978688 is a wasteful number, since it uses less digits than its factorization.

161198978688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191 (or 170 counting only the distinct ones).

The product of its digits is 83607552, while the sum is 72.

The spelling of 161198978688 in words is "one hundred sixty-one billion, one hundred ninety-eight million, nine hundred seventy-eight thousand, six hundred eighty-eight".