161159778 has 24 divisors (see below), whose sum is σ = 376040028. Its totient is φ = 49587552.

The previous prime is 161159773. The next prime is 161159819. The reversal of 161159778 is 877951161.

It can be written as a sum of positive squares in 2 ways, for example, as 160959969 + 199809 = 12687^2 + 447^2 .

It is not an unprimeable number, because it can be changed into a prime (161159771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 344125 + ... + 344592.

Almost surely, 2^161159778 is an apocalyptic number.

161159778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

161159778 is an abundant number, since it is smaller than the sum of its proper divisors (214880250).

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

161159778 is a wasteful number, since it uses less digits than its factorization.

161159778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688738 (or 688735 counting only the distinct ones).

The product of its digits is 105840, while the sum is 45.

The square root of 161159778 is about 12694.8721143618. The cubic root of 161159778 is about 544.1920840747.

The spelling of 161159778 in words is "one hundred sixty-one million, one hundred fifty-nine thousand, seven hundred seventy-eight".