66690565 has 8 divisors (see below), whose sum is σ = 80205048. Its totient is φ = 53234880.

The previous prime is 66690553. The next prime is 66690587. The reversal of 66690565 is 56509666.

It can be written as a sum of positive squares in 4 ways, for example, as 3869089 + 62821476 = 1967^2 + 7926^2 .

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

It is not a de Polignac number, because 66690565 - 2¹³ = 66682373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12162 + ... + 16771.

It is an arithmetic number, because the mean of its divisors is an integer number (10025631).

Almost surely, 2^66690565 is an apocalyptic number.

It is an amenable number.

66690565 is a deficient number, since it is larger than the sum of its proper divisors (13514483).

66690565 is a wasteful number, since it uses less digits than its factorization.

66690565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29399.

The product of its (nonzero) digits is 291600, while the sum is 43.

The square root of 66690565 is about 8166.4291462058. The cubic root of 66690565 is about 405.5285787467.

The spelling of 66690565 in words is "sixty-six million, six hundred ninety thousand, five hundred sixty-five".