646081 has 4 divisors (see below), whose sum is σ = 655792. Its totient is φ = 636372.

The previous prime is 646073. The next prime is 646099. The reversal of 646081 is 180646.

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 not a de Polignac number, because 646081 - 2³ = 646073 is a prime.

It is a super-2 number, since 2×646081² = 834841317122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4755 + ... + 4888.

It is an arithmetic number, because the mean of its divisors is an integer number (163948).

2⁶⁴⁶⁰⁸¹ is an apocalyptic number.

It is an amenable number.

646081 is a deficient number, since it is larger than the sum of its proper divisors (9711).

646081 is an equidigital number, since it uses as much as digits as its factorization.

646081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9710.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 646081 is about 803.7916396679. The cubic root of 646081 is about 86.4494676285.

The spelling of 646081 in words is "six hundred forty-six thousand, eighty-one".