647806 has 4 divisors (see below), whose sum is σ = 971712. Its totient is φ = 323902.

The previous prime is 647789. The next prime is 647809. The reversal of 647806 is 608746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 608746 = 2 ⋅304373.

It is a super-2 number, since 2×647806² = 839305227272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161950 + ... + 161953.

It is an arithmetic number, because the mean of its divisors is an integer number (242928).

2⁶⁴⁷⁸⁰⁶ is an apocalyptic number.

647806 is a deficient number, since it is larger than the sum of its proper divisors (323906).

647806 is a wasteful number, since it uses less digits than its factorization.

647806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323905.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 647806 is about 804.8639636609. The cubic root of 647806 is about 86.5263376646.

Subtracting from 647806 its reverse (608746), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 647806 in words is "six hundred forty-seven thousand, eight hundred six".