393640639 has 8 divisors (see below), whose sum is σ = 450802688. Its totient is φ = 336710520.

The previous prime is 393640603. The next prime is 393640649. The reversal of 393640639 is 936046393.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393640639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 393640595 and 393640604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393640649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54327 + ... + 61144.

It is an arithmetic number, because the mean of its divisors is an integer number (56350336).

Almost surely, 2^393640639 is an apocalyptic number.

393640639 is a deficient number, since it is larger than the sum of its proper divisors (57162049).

393640639 is a wasteful number, since it uses less digits than its factorization.

393640639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115965.

The product of its (nonzero) digits is 314928, while the sum is 43.

The square root of 393640639 is about 19840.3790034364. The cubic root of 393640639 is about 732.8807412312.

The spelling of 393640639 in words is "three hundred ninety-three million, six hundred forty thousand, six hundred thirty-nine".