6399971523 has 12 divisors (see below), whose sum is σ = 10084803768. Its totient is φ = 3878770560.

The previous prime is 6399971519. The next prime is 6399971551. The reversal of 6399971523 is 3251799936.

It is a happy number.

It is not a de Polignac number, because 6399971523 - 2² = 6399971519 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6399971523.

It is not an unprimeable number, because it can be changed into a prime (6399971503) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32322990 + ... + 32323187.

It is an arithmetic number, because the mean of its divisors is an integer number (840400314).

Almost surely, 2^6399971523 is an apocalyptic number.

6399971523 is a deficient number, since it is larger than the sum of its proper divisors (3684832245).

6399971523 is a wasteful number, since it uses less digits than its factorization.

6399971523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64646194 (or 64646191 counting only the distinct ones).

The product of its digits is 2755620, while the sum is 54.

The square root of 6399971523 is about 79999.8220185520. The cubic root of 6399971523 is about 1856.6327797218.

The spelling of 6399971523 in words is "six billion, three hundred ninety-nine million, nine hundred seventy-one thousand, five hundred twenty-three".