646709501 has 2 divisors, whose sum is σ = 646709502. Its totient is φ = 646709500.

The previous prime is 646709491. The next prime is 646709513. The reversal of 646709501 is 105907646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 538008025 + 108701476 = 23195^2 + 10426^2 .

It is a cyclic number.

It is not a de Polignac number, because 646709501 - 2¹⁰ = 646708477 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646709521) 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, 323354750 + 323354751.

It is an arithmetic number, because the mean of its divisors is an integer number (323354751).

Almost surely, 2^646709501 is an apocalyptic number.

It is an amenable number.

646709501 is a deficient number, since it is larger than the sum of its proper divisors (1).

646709501 is an equidigital number, since it uses as much as digits as its factorization.

646709501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 38.

The square root of 646709501 is about 25430.4836957538. The cubic root of 646709501 is about 864.7749093003.

The spelling of 646709501 in words is "six hundred forty-six million, seven hundred nine thousand, five hundred one".