646356331 has 2 divisors, whose sum is σ = 646356332. Its totient is φ = 646356330.

The previous prime is 646356329. The next prime is 646356353. The reversal of 646356331 is 133653646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646356331 - 2¹ = 646356329 is a prime.

It is a super-2 number, since 2×646356331² = 835553013247563122, which contains 22 as substring.

Together with 646356329, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (646356391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323178165 + 323178166.

It is an arithmetic number, because the mean of its divisors is an integer number (323178166).

Almost surely, 2^646356331 is an apocalyptic number.

646356331 is a deficient number, since it is larger than the sum of its proper divisors (1).

646356331 is an equidigital number, since it uses as much as digits as its factorization.

646356331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 37.

The square root of 646356331 is about 25423.5389157371. The cubic root of 646356331 is about 864.6174619113.

It can be divided in two parts, 64 and 6356331, that added together give a triangular number (6356395 = T₃₅₆₅).

The spelling of 646356331 in words is "six hundred forty-six million, three hundred fifty-six thousand, three hundred thirty-one".