161378018 has 4 divisors (see below), whose sum is σ = 242067030. Its totient is φ = 80689008.

The previous prime is 161377981. The next prime is 161378023. The reversal of 161378018 is 810873161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 810873161 = 7 ⋅115839023.

It can be written as a sum of positive squares in only one way, i.e., 87366409 + 74011609 = 9347^2 + 8603^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40344503 + ... + 40344506.

Almost surely, 2^161378018 is an apocalyptic number.

161378018 is a deficient number, since it is larger than the sum of its proper divisors (80689012).

161378018 is an equidigital number, since it uses as much as digits as its factorization.

161378018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80689011.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 161378018 is about 12703.4648029583. The cubic root of 161378018 is about 544.4376186875.

The spelling of 161378018 in words is "one hundred sixty-one million, three hundred seventy-eight thousand, eighteen".