399881161 has 2 divisors, whose sum is σ = 399881162. Its totient is φ = 399881160.

The previous prime is 399881117. The next prime is 399881171. The reversal of 399881161 is 161188993.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 318087225 + 81793936 = 17835^2 + 9044^2 .

It is a cyclic number.

It is not a de Polignac number, because 399881161 - 2⁷ = 399881033 is a prime.

It is not a weakly prime, because it can be changed into another prime (399881101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199940580 + 199940581.

It is an arithmetic number, because the mean of its divisors is an integer number (199940581).

Almost surely, 2^399881161 is an apocalyptic number.

It is an amenable number.

399881161 is a deficient number, since it is larger than the sum of its proper divisors (1).

399881161 is an equidigital number, since it uses as much as digits as its factorization.

399881161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 46.

The square root of 399881161 is about 19997.0288042999. The cubic root of 399881161 is about 736.7333247308.

The spelling of 399881161 in words is "three hundred ninety-nine million, eight hundred eighty-one thousand, one hundred sixty-one".