647686745 has 4 divisors (see below), whose sum is σ = 777224100. Its totient is φ = 518149392.

The previous prime is 647686673. The next prime is 647686747. The reversal of 647686745 is 547686746.

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

It can be written as a sum of positive squares in 2 ways, for example, as 91623184 + 556063561 = 9572^2 + 23581^2 .

It is a cyclic number.

It is not a de Polignac number, because 647686745 - 2¹⁶ = 647621209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (647686747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64768670 + ... + 64768679.

It is an arithmetic number, because the mean of its divisors is an integer number (194306025).

Almost surely, 2^647686745 is an apocalyptic number.

It is an amenable number.

647686745 is a deficient number, since it is larger than the sum of its proper divisors (129537355).

647686745 is a wasteful number, since it uses less digits than its factorization.

647686745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129537354.

The product of its digits is 6773760, while the sum is 53.

The square root of 647686745 is about 25449.6904696305. The cubic root of 647686745 is about 865.2102777677.

Subtracting from 647686745 its reverse (547686746), we obtain a palindrome (99999999).

The spelling of 647686745 in words is "six hundred forty-seven million, six hundred eighty-six thousand, seven hundred forty-five".