647857 has 4 divisors (see below), whose sum is σ = 740416. Its totient is φ = 555300.

The previous prime is 647851. The next prime is 647861. The reversal of 647857 is 758746.

It is a happy number.

647857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647851) 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, 46269 + ... + 46282.

It is an arithmetic number, because the mean of its divisors is an integer number (185104).

2⁶⁴⁷⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

647857 is a deficient number, since it is larger than the sum of its proper divisors (92559).

647857 is an equidigital number, since it uses as much as digits as its factorization.

647857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92558.

The product of its digits is 47040, while the sum is 37.

The square root of 647857 is about 804.8956454100. The cubic root of 647857 is about 86.5286082659.

Subtracting 647857 from its reverse (758746), we obtain a square (110889 = 333²).

It can be divided in two parts, 64 and 7857, that added together give a square (7921 = 89²).

The spelling of 647857 in words is "six hundred forty-seven thousand, eight hundred fifty-seven".