66019565 has 4 divisors (see below), whose sum is σ = 79223484. Its totient is φ = 52815648.

The previous prime is 66019549. The next prime is 66019567. The reversal of 66019565 is 56591066.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8213956 + 57805609 = 2866^2 + 7603^2 .

It is a cyclic number.

It is not a de Polignac number, because 66019565 - 2⁴ = 66019549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66019567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6601952 + ... + 6601961.

It is an arithmetic number, because the mean of its divisors is an integer number (19805871).

Almost surely, 2^66019565 is an apocalyptic number.

It is an amenable number.

66019565 is a deficient number, since it is larger than the sum of its proper divisors (13203919).

66019565 is a wasteful number, since it uses less digits than its factorization.

66019565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13203918.

The product of its (nonzero) digits is 48600, while the sum is 38.

The square root of 66019565 is about 8125.2424579209. The cubic root of 66019565 is about 404.1639308751.

The spelling of 66019565 in words is "sixty-six million, nineteen thousand, five hundred sixty-five".