399781845 has 32 divisors (see below), whose sum is σ = 711786240. Its totient is φ = 212898240.

The previous prime is 399781819. The next prime is 399781873. The reversal of 399781845 is 548187993.

399781845 is a `hidden beast` number, since 399 + 78 + 184 + 5 = 666.

It is not a de Polignac number, because 399781845 - 2⁵ = 399781813 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 399781791 and 399781800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 109032 + ... + 112638.

It is an arithmetic number, because the mean of its divisors is an integer number (22243320).

Almost surely, 2^399781845 is an apocalyptic number.

It is an amenable number.

399781845 is a deficient number, since it is larger than the sum of its proper divisors (312004395).

399781845 is a wasteful number, since it uses less digits than its factorization.

399781845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4442 (or 4436 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The square root of 399781845 is about 19994.5453811783. The cubic root of 399781845 is about 736.6723270542.

The spelling of 399781845 in words is "three hundred ninety-nine million, seven hundred eighty-one thousand, eight hundred forty-five".