6349978661 has 8 divisors (see below), whose sum is σ = 6920830560. Its totient is φ = 5790897072.

The previous prime is 6349978643. The next prime is 6349978673. The reversal of 6349978661 is 1668799436.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 6349978661 - 2¹⁰ = 6349977637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 6349978661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6349968661) 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, 2941451 + ... + 2943608.

It is an arithmetic number, because the mean of its divisors is an integer number (865103820).

Almost surely, 2^6349978661 is an apocalyptic number.

It is an amenable number.

6349978661 is a deficient number, since it is larger than the sum of its proper divisors (570851899).

6349978661 is a wasteful number, since it uses less digits than its factorization.

6349978661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5885155.

The product of its digits is 11757312, while the sum is 59.

The square root of 6349978661 is about 79686.7533596394. The cubic root of 6349978661 is about 1851.7858247296.

The spelling of 6349978661 in words is "six billion, three hundred forty-nine million, nine hundred seventy-eight thousand, six hundred sixty-one".