646825 has 6 divisors (see below), whose sum is σ = 802094. Its totient is φ = 517440.

The previous prime is 646823. The next prime is 646831. The reversal of 646825 is 528646.

It can be written as a sum of positive squares in 3 ways, for example, as 36864 + 609961 = 192^2 + 781^2 .

It is not a de Polignac number, because 646825 - 2¹ = 646823 is a prime.

It is a Duffinian number.

646825 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (646823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12912 + ... + 12961.

2⁶⁴⁶⁸²⁵ is an apocalyptic number.

It is an amenable number.

646825 is a deficient number, since it is larger than the sum of its proper divisors (155269).

646825 is a wasteful number, since it uses less digits than its factorization.

646825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25883 (or 25878 counting only the distinct ones).

The product of its digits is 11520, while the sum is 31.

The square root of 646825 is about 804.2543130130. The cubic root of 646825 is about 86.4826387690.

It can be divided in two parts, 64 and 6825, that added together give a square (6889 = 83²).

The spelling of 646825 in words is "six hundred forty-six thousand, eight hundred twenty-five".