399134810881 has 16 divisors (see below), whose sum is σ = 409614661456. Its totient is φ = 388800000000.

The previous prime is 399134810873. The next prime is 399134810891. The reversal of 399134810881 is 188018431993.

It is a happy number.

It is the 257920-th star number.

It can be written as a sum of positive squares in 8 ways, for example, as 123211530225 + 275923280656 = 351015^2 + 525284^2 .

It is a 8-Lehmer number, since φ(399134810881) divides (399134810881-1)⁸.

It is a cyclic number.

It is not a de Polignac number, because 399134810881 - 2³ = 399134810873 is a prime.

It is a super-2 number, since 2×399134810881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399134810891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2585881 + ... + 2735881.

It is an arithmetic number, because the mean of its divisors is an integer number (25600916341).

Almost surely, 2^399134810881 is an apocalyptic number.

It is an amenable number.

399134810881 is a deficient number, since it is larger than the sum of its proper divisors (10479850575).

399134810881 is a wasteful number, since it uses less digits than its factorization.

399134810881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150484.

The product of its (nonzero) digits is 1492992, while the sum is 55.

The spelling of 399134810881 in words is "three hundred ninety-nine billion, one hundred thirty-four million, eight hundred ten thousand, eight hundred eighty-one".