646361861 has 2 divisors, whose sum is σ = 646361862. Its totient is φ = 646361860.

The previous prime is 646361839. The next prime is 646361867. The reversal of 646361861 is 168163646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 503104900 + 143256961 = 22430^2 + 11969^2 .

It is a cyclic number.

It is not a de Polignac number, because 646361861 - 2¹⁸ = 646099717 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646361867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323180930 + 323180931.

It is an arithmetic number, because the mean of its divisors is an integer number (323180931).

Almost surely, 2^646361861 is an apocalyptic number.

It is an amenable number.

646361861 is a deficient number, since it is larger than the sum of its proper divisors (1).

646361861 is an equidigital number, since it uses as much as digits as its factorization.

646361861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 41.

The square root of 646361861 is about 25423.6476729835. The cubic root of 646361861 is about 864.6199276930.

The spelling of 646361861 in words is "six hundred forty-six million, three hundred sixty-one thousand, eight hundred sixty-one".