399615841 has 4 divisors (see below), whose sum is σ = 399680532. Its totient is φ = 399551152.

The previous prime is 399615829. The next prime is 399615859. The reversal of 399615841 is 148516993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106007616 + 293608225 = 10296^2 + 17135^2 .

It is a cyclic number.

It is not a de Polignac number, because 399615841 - 2⁹ = 399615329 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399615791 and 399615800.

It is not an unprimeable number, because it can be changed into a prime (399615871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21970 + ... + 35803.

It is an arithmetic number, because the mean of its divisors is an integer number (99920133).

Almost surely, 2^399615841 is an apocalyptic number.

It is an amenable number.

399615841 is a deficient number, since it is larger than the sum of its proper divisors (64691).

399615841 is an equidigital number, since it uses as much as digits as its factorization.

399615841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64690.

The product of its digits is 233280, while the sum is 46.

The square root of 399615841 is about 19990.3937179836. The cubic root of 399615841 is about 736.5703485336.

The spelling of 399615841 in words is "three hundred ninety-nine million, six hundred fifteen thousand, eight hundred forty-one".