396640109 has 4 divisors (see below), whose sum is σ = 406314300. Its totient is φ = 386965920.

The previous prime is 396640103. The next prime is 396640169. The reversal of 396640109 is 901046693.

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 218951209 + 177688900 = 14797^2 + 13330^2 .

It is a cyclic number.

It is not a de Polignac number, because 396640109 - 2¹² = 396636013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (396640103) 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, 4837034 + ... + 4837115.

It is an arithmetic number, because the mean of its divisors is an integer number (101578575).

Almost surely, 2^396640109 is an apocalyptic number.

It is an amenable number.

396640109 is a deficient number, since it is larger than the sum of its proper divisors (9674191).

396640109 is an equidigital number, since it uses as much as digits as its factorization.

396640109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9674190.

The product of its (nonzero) digits is 34992, while the sum is 38.

The square root of 396640109 is about 19915.8255917248. The cubic root of 396640109 is about 734.7375057223.

The spelling of 396640109 in words is "three hundred ninety-six million, six hundred forty thousand, one hundred nine".