6661736399 has 24 divisors (see below), whose sum is σ = 7486035360. Its totient is φ = 5914681344.

The previous prime is 6661736377. The next prime is 6661736423. The reversal of 6661736399 is 9936371666.

It is not a de Polignac number, because 6661736399 - 2⁸ = 6661736143 is a prime.

It is a super-2 number, since 2×6661736399² = 88757463699522974402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661736329) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 478367 + ... + 492095.

It is an arithmetic number, because the mean of its divisors is an integer number (311918140).

Almost surely, 2^6661736399 is an apocalyptic number.

6661736399 is a deficient number, since it is larger than the sum of its proper divisors (824298961).

6661736399 is a wasteful number, since it uses less digits than its factorization.

6661736399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13859 (or 13842 counting only the distinct ones).

The product of its digits is 6613488, while the sum is 56.

The square root of 6661736399 is about 81619.4609085358. The cubic root of 6661736399 is about 1881.6079873931.

The spelling of 6661736399 in words is "six billion, six hundred sixty-one million, seven hundred thirty-six thousand, three hundred ninety-nine".