6399047661 has 4 divisors (see below), whose sum is σ = 8532063552. Its totient is φ = 4266031772.

The previous prime is 6399047617. The next prime is 6399047671. The reversal of 6399047661 is 1667409936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6399047661 - 2²⁵ = 6365493229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6399047671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1066507941 + ... + 1066507946.

It is an arithmetic number, because the mean of its divisors is an integer number (2133015888).

Almost surely, 2^6399047661 is an apocalyptic number.

It is an amenable number.

6399047661 is a deficient number, since it is larger than the sum of its proper divisors (2133015891).

6399047661 is a wasteful number, since it uses less digits than its factorization.

6399047661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2133015890.

The product of its (nonzero) digits is 1469664, while the sum is 51.

The square root of 6399047661 is about 79994.0476598103. The cubic root of 6399047661 is about 1856.5434379172.

The spelling of 6399047661 in words is "six billion, three hundred ninety-nine million, forty-seven thousand, six hundred sixty-one".