161499978 has 12 divisors (see below), whose sum is σ = 349916658. Its totient is φ = 53833320.

The previous prime is 161499941. The next prime is 161499979. The reversal of 161499978 is 879994161.

161499978 is a `hidden beast` number, since 1 + 61 + 499 + 97 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 101545929 + 59954049 = 10077^2 + 7743^2 .

It is not an unprimeable number, because it can be changed into a prime (161499979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4486093 + ... + 4486128.

Almost surely, 2^161499978 is an apocalyptic number.

161499978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

161499978 is an abundant number, since it is smaller than the sum of its proper divisors (188416680).

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

161499978 is a wasteful number, since it uses less digits than its factorization.

161499978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8972229 (or 8972226 counting only the distinct ones).

The product of its digits is 979776, while the sum is 54.

The square root of 161499978 is about 12708.2641615604. The cubic root of 161499978 is about 544.5747354457.

The spelling of 161499978 in words is "one hundred sixty-one million, four hundred ninety-nine thousand, nine hundred seventy-eight".