399401521171 has 2 divisors, whose sum is σ = 399401521172. Its totient is φ = 399401521170.

The previous prime is 399401521157. The next prime is 399401521187. The reversal of 399401521171 is 171125104993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399401521171 - 2⁵ = 399401521139 is a prime.

It is a super-2 number, since 2×399401521171² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399401531171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199700760585 + 199700760586.

It is an arithmetic number, because the mean of its divisors is an integer number (199700760586).

Almost surely, 2^399401521171 is an apocalyptic number.

399401521171 is a deficient number, since it is larger than the sum of its proper divisors (1).

399401521171 is an equidigital number, since it uses as much as digits as its factorization.

399401521171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040, while the sum is 43.

The spelling of 399401521171 in words is "three hundred ninety-nine billion, four hundred one million, five hundred twenty-one thousand, one hundred seventy-one".