646831 has 2 divisors, whose sum is σ = 646832. Its totient is φ = 646830.

The previous prime is 646823. The next prime is 646837. The reversal of 646831 is 138646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646831 - 2³ = 646823 is a prime.

It is a super-2 number, since 2×646831² = 836780685122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 646831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323415 + 323416.

It is an arithmetic number, because the mean of its divisors is an integer number (323416).

2⁶⁴⁶⁸³¹ is an apocalyptic number.

646831 is a deficient number, since it is larger than the sum of its proper divisors (1).

646831 is an equidigital number, since it uses as much as digits as its factorization.

646831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 28.

The square root of 646831 is about 804.2580431677. The cubic root of 646831 is about 86.4829061748.

The spelling of 646831 in words is "six hundred forty-six thousand, eight hundred thirty-one".