6396943639 has 4 divisors (see below), whose sum is σ = 6436188856. Its totient is φ = 6357698424.

The previous prime is 6396943621. The next prime is 6396943667. The reversal of 6396943639 is 9363496936.

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

It is a cyclic number.

It is not a de Polignac number, because 6396943639 - 2²¹ = 6394846487 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 (6396943699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19622364 + ... + 19622689.

It is an arithmetic number, because the mean of its divisors is an integer number (1609047214).

Almost surely, 2^6396943639 is an apocalyptic number.

6396943639 is a deficient number, since it is larger than the sum of its proper divisors (39245217).

6396943639 is a wasteful number, since it uses less digits than its factorization.

6396943639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39245216.

The product of its digits is 17006112, while the sum is 58.

The square root of 6396943639 is about 79980.8954626041. The cubic root of 6396943639 is about 1856.3399369878.

The spelling of 6396943639 in words is "six billion, three hundred ninety-six million, nine hundred forty-three thousand, six hundred thirty-nine".