647640643 has 8 divisors (see below), whose sum is σ = 701075648. Its totient is φ = 594722304.

The previous prime is 647640611. The next prime is 647640649. The reversal of 647640643 is 346046746.

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 647640643 - 2⁵ = 647640611 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 647640596 and 647640605.

It is not an unprimeable number, because it can be changed into a prime (647640649) 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, 126555 + ... + 131572.

It is an arithmetic number, because the mean of its divisors is an integer number (87634456).

Almost surely, 2^647640643 is an apocalyptic number.

647640643 is a deficient number, since it is larger than the sum of its proper divisors (53435005).

647640643 is a wasteful number, since it uses less digits than its factorization.

647640643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258333.

The product of its (nonzero) digits is 290304, while the sum is 40.

The square root of 647640643 is about 25448.7847057576. The cubic root of 647640643 is about 865.1897488773.

The spelling of 647640643 in words is "six hundred forty-seven million, six hundred forty thousand, six hundred forty-three".