64667709 has 12 divisors (see below), whose sum is σ = 96630300. Its totient is φ = 41625024.

The previous prime is 64667693. The next prime is 64667719. The reversal of 64667709 is 90776646.

It can be written as a sum of positive squares in 2 ways, for example, as 43599609 + 21068100 = 6603^2 + 4590^2 .

It is not a de Polignac number, because 64667709 - 2⁴ = 64667693 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64667719) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 123624 + ... + 124145.

It is an arithmetic number, because the mean of its divisors is an integer number (8052525).

Almost surely, 2^64667709 is an apocalyptic number.

It is an amenable number.

64667709 is a deficient number, since it is larger than the sum of its proper divisors (31962591).

64667709 is a wasteful number, since it uses less digits than its factorization.

64667709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247804 (or 247801 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The square root of 64667709 is about 8041.6235301088. The cubic root of 64667709 is about 401.3862506397.

The spelling of 64667709 in words is "sixty-four million, six hundred sixty-seven thousand, seven hundred nine".