647611681 has 8 divisors (see below), whose sum is σ = 651440000. Its totient is φ = 643794480.

The previous prime is 647611639. The next prime is 647611709. The reversal of 647611681 is 186116746.

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 647611681 - 2⁹ = 647611169 is a prime.

It is a super-2 number, since 2×647611681² = 838801778735291522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647611631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132835 + ... + 137623.

It is an arithmetic number, because the mean of its divisors is an integer number (81430000).

Almost surely, 2^647611681 is an apocalyptic number.

It is an amenable number.

647611681 is a deficient number, since it is larger than the sum of its proper divisors (3828319).

647611681 is a wasteful number, since it uses less digits than its factorization.

647611681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5559.

The product of its digits is 48384, while the sum is 40.

The square root of 647611681 is about 25448.2156741882. The cubic root of 647611681 is about 865.1768518079.

The spelling of 647611681 in words is "six hundred forty-seven million, six hundred eleven thousand, six hundred eighty-one".