647628791 has 4 divisors (see below), whose sum is σ = 647810784. Its totient is φ = 647446800.

The previous prime is 647628769. The next prime is 647628799. The reversal of 647628791 is 197826746.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 647628791 - 2⁶ = 647628727 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 (647628799) 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 3 ways as a sum of consecutive naturals, for example, 85550 + ... + 92811.

It is an arithmetic number, because the mean of its divisors is an integer number (161952696).

Almost surely, 2^647628791 is an apocalyptic number.

647628791 is a deficient number, since it is larger than the sum of its proper divisors (181993).

647628791 is a wasteful number, since it uses less digits than its factorization.

647628791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181992.

The product of its digits is 1016064, while the sum is 50.

The square root of 647628791 is about 25448.5518448496. The cubic root of 647628791 is about 865.1844711092.

The spelling of 647628791 in words is "six hundred forty-seven million, six hundred twenty-eight thousand, seven hundred ninety-one".