646881 has 8 divisors (see below), whose sum is σ = 874944. Its totient is φ = 425040.

The previous prime is 646879. The next prime is 646883. The reversal of 646881 is 188646.

It is an interprime number because it is at equal distance from previous prime (646879) and next prime (646883).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 646881 - 2¹ = 646879 is a prime.

It is a super-2 number, since 2×646881² = 836910056322, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (646883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1306 + ... + 1731.

It is an arithmetic number, because the mean of its divisors is an integer number (109368).

2⁶⁴⁶⁸⁸¹ is an apocalyptic number.

It is an amenable number.

646881 is a deficient number, since it is larger than the sum of its proper divisors (228063).

646881 is a wasteful number, since it uses less digits than its factorization.

646881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3111.

The product of its digits is 9216, while the sum is 33.

The square root of 646881 is about 804.2891271179. The cubic root of 646881 is about 86.4851344920.

The spelling of 646881 in words is "six hundred forty-six thousand, eight hundred eighty-one".