646478165 has 8 divisors (see below), whose sum is σ = 777710808. Its totient is φ = 515891200.

The previous prime is 646478149. The next prime is 646478167. The reversal of 646478165 is 561874646.

It can be written as a sum of positive squares in 4 ways, for example, as 157979761 + 488498404 = 12569^2 + 22102^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 646478165 - 2⁴ = 646478149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646478167) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 159212 + ... + 163221.

It is an arithmetic number, because the mean of its divisors is an integer number (97213851).

Almost surely, 2^646478165 is an apocalyptic number.

It is an amenable number.

646478165 is a deficient number, since it is larger than the sum of its proper divisors (131232643).

646478165 is a wasteful number, since it uses less digits than its factorization.

646478165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322839.

The product of its digits is 967680, while the sum is 47.

The square root of 646478165 is about 25425.9348893998. The cubic root of 646478165 is about 864.6717834368.

The spelling of 646478165 in words is "six hundred forty-six million, four hundred seventy-eight thousand, one hundred sixty-five".