161398018 has 4 divisors (see below), whose sum is σ = 242097030. Its totient is φ = 80699008.

The previous prime is 161398007. The next prime is 161398019. The reversal of 161398018 is 810893161.

161398018 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 150724729 + 10673289 = 12277^2 + 3267^2 .

It is not an unprimeable number, because it can be changed into a prime (161398019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40349503 + ... + 40349506.

Almost surely, 2^161398018 is an apocalyptic number.

161398018 is a deficient number, since it is larger than the sum of its proper divisors (80699012).

161398018 is an equidigital number, since it uses as much as digits as its factorization.

161398018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80699011.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 161398018 is about 12704.2519653854. The cubic root of 161398018 is about 544.4601089513.

The spelling of 161398018 in words is "one hundred sixty-one million, three hundred ninety-eight thousand, eighteen".