647715661 has 8 divisors (see below), whose sum is σ = 655611264. Its totient is φ = 639858240.

The previous prime is 647715647. The next prime is 647715683. The reversal of 647715661 is 166517746.

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 647715661 - 2⁷ = 647715533 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 (647715631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25356 + ... + 44026.

It is an arithmetic number, because the mean of its divisors is an integer number (81951408).

Almost surely, 2^647715661 is an apocalyptic number.

It is an amenable number.

647715661 is a deficient number, since it is larger than the sum of its proper divisors (7895603).

647715661 is a wasteful number, since it uses less digits than its factorization.

647715661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19091.

The product of its digits is 211680, while the sum is 43.

The square root of 647715661 is about 25450.2585645019. The cubic root of 647715661 is about 865.2231533583.

The spelling of 647715661 in words is "six hundred forty-seven million, seven hundred fifteen thousand, six hundred sixty-one".