399218171 has 4 divisors (see below), whose sum is σ = 435510744. Its totient is φ = 362925600.

The previous prime is 399218167. The next prime is 399218201. The reversal of 399218171 is 171812993.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 399218171 - 2² = 399218167 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399218111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18146270 + ... + 18146291.

It is an arithmetic number, because the mean of its divisors is an integer number (108877686).

Almost surely, 2^399218171 is an apocalyptic number.

399218171 is a deficient number, since it is larger than the sum of its proper divisors (36292573).

399218171 is a wasteful number, since it uses less digits than its factorization.

399218171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36292572.

The product of its digits is 27216, while the sum is 41.

The square root of 399218171 is about 19980.4447147705. Note that the first 3 decimals coincide. The cubic root of 399218171 is about 736.3259395153.

The spelling of 399218171 in words is "three hundred ninety-nine million, two hundred eighteen thousand, one hundred seventy-one".