399709809945 has 16 divisors (see below), whose sum is σ = 710595217920. Its totient is φ = 213178565232.

The previous prime is 399709809929. The next prime is 399709809973. The reversal of 399709809945 is 549908907993.

399709809945 is a `hidden beast` number, since 399 + 70 + 9 + 80 + 9 + 94 + 5 = 666.

It is not a de Polignac number, because 399709809945 - 2⁴ = 399709809929 is a prime.

It is an unprimeable number.

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, 1480406569 + ... + 1480406838.

It is an arithmetic number, because the mean of its divisors is an integer number (44412201120).

Almost surely, 2^399709809945 is an apocalyptic number.

It is an amenable number.

399709809945 is a deficient number, since it is larger than the sum of its proper divisors (310885407975).

399709809945 is a wasteful number, since it uses less digits than its factorization.

399709809945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2960813421 (or 2960813415 counting only the distinct ones).

The product of its (nonzero) digits is 198404640, while the sum is 72.

The spelling of 399709809945 in words is "three hundred ninety-nine billion, seven hundred nine million, eight hundred nine thousand, nine hundred forty-five".