161561867328 has 56 divisors (see below), whose sum is σ = 474961976160. Its totient is φ = 53853955200.

The previous prime is 161561867321. The next prime is 161561867339. The reversal of 161561867328 is 823768165161.

It is a happy number.

161561867328 is a `hidden beast` number, since 1 + 6 + 1 + 561 + 8 + 6 + 73 + 2 + 8 = 666.

It is a super-2 number, since 2×161561867328² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (161561867321) 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, 46746498 + ... + 46749953.

It is an arithmetic number, because the mean of its divisors is an integer number (8481463860).

Almost surely, 2^161561867328 is an apocalyptic number.

161561867328 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

161561867328 is an abundant number, since it is smaller than the sum of its proper divisors (313400108832).

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

161561867328 is an equidigital number, since it uses as much as digits as its factorization.

161561867328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93496472 (or 93496456 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 161561867328 in words is "one hundred sixty-one billion, five hundred sixty-one million, eight hundred sixty-seven thousand, three hundred twenty-eight".