399040026 has 64 divisors (see below), whose sum is σ = 1015372800. Its totient is φ = 103640880.

The previous prime is 399040009. The next prime is 399040039. The reversal of 399040026 is 620040993.

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 13825 + ... + 31451.

It is an arithmetic number, because the mean of its divisors is an integer number (15865200).

Almost surely, 2^399040026 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399040026, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (507686400).

399040026 is an abundant number, since it is smaller than the sum of its proper divisors (616332774).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399040026 is a wasteful number, since it uses less digits than its factorization.

399040026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17664 (or 17650 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 399040026 is about 19975.9862334754. The cubic root of 399040026 is about 736.2163984922.

The spelling of 399040026 in words is "three hundred ninety-nine million, forty thousand, twenty-six".