399648617 has 4 divisors (see below), whose sum is σ = 403605636. Its totient is φ = 395691600.

The previous prime is 399648611. The next prime is 399648619. The reversal of 399648617 is 716846993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 716846993 = 41 ⋅17484073.

It can be written as a sum of positive squares in 2 ways, for example, as 216560656 + 183087961 = 14716^2 + 13531^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399648617 is a prime.

It is a super-3 number, since 3×399648617³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399648611) 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, 1978358 + ... + 1978559.

It is an arithmetic number, because the mean of its divisors is an integer number (100901409).

Almost surely, 2^399648617 is an apocalyptic number.

It is an amenable number.

399648617 is a deficient number, since it is larger than the sum of its proper divisors (3957019).

399648617 is a wasteful number, since it uses less digits than its factorization.

399648617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3957018.

The product of its digits is 1959552, while the sum is 53.

The square root of 399648617 is about 19991.2134949332. The cubic root of 399648617 is about 736.5904855145.

The spelling of 399648617 in words is "three hundred ninety-nine million, six hundred forty-eight thousand, six hundred seventeen".