163997278 has 4 divisors (see below), whose sum is σ = 245995920. Its totient is φ = 81998638.

The previous prime is 163997261. The next prime is 163997279. The reversal of 163997278 is 872799361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 872799361 = 7 ⋅124685623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163997279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40999318 + ... + 40999321.

It is an arithmetic number, because the mean of its divisors is an integer number (61498980).

Almost surely, 2^163997278 is an apocalyptic number.

163997278 is a deficient number, since it is larger than the sum of its proper divisors (81998642).

163997278 is an equidigital number, since it uses as much as digits as its factorization.

163997278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81998641.

The product of its digits is 1143072, while the sum is 52.

The square root of 163997278 is about 12806.1421981797. The cubic root of 163997278 is about 547.3673391254.

The spelling of 163997278 in words is "one hundred sixty-three million, nine hundred ninety-seven thousand, two hundred seventy-eight".