646403377 has 2 divisors, whose sum is σ = 646403378. Its totient is φ = 646403376.

The previous prime is 646403327. The next prime is 646403411. The reversal of 646403377 is 773304646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 394260736 + 252142641 = 19856^2 + 15879^2 .

It is a cyclic number.

It is not a de Polignac number, because 646403377 - 2⁷ = 646403249 is a prime.

It is not a weakly prime, because it can be changed into another prime (646403327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323201688 + 323201689.

It is an arithmetic number, because the mean of its divisors is an integer number (323201689).

Almost surely, 2^646403377 is an apocalyptic number.

It is an amenable number.

646403377 is a deficient number, since it is larger than the sum of its proper divisors (1).

646403377 is an equidigital number, since it uses as much as digits as its factorization.

646403377 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 254016, while the sum is 40.

The square root of 646403377 is about 25424.4641438124. The cubic root of 646403377 is about 864.6384388886.

The spelling of 646403377 in words is "six hundred forty-six million, four hundred three thousand, three hundred seventy-seven".