66999565 has 8 divisors (see below), whose sum is σ = 80881920. Its totient is φ = 53278032.

The previous prime is 66999551. The next prime is 66999577. The reversal of 66999565 is 56599966.

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

It is a cyclic number.

It is not a de Polignac number, because 66999565 - 2²³ = 58610957 is a prime.

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, 39285 + ... + 40954.

It is an arithmetic number, because the mean of its divisors is an integer number (10110240).

Almost surely, 2^66999565 is an apocalyptic number.

It is an amenable number.

66999565 is a deficient number, since it is larger than the sum of its proper divisors (13882355).

66999565 is a wasteful number, since it uses less digits than its factorization.

66999565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80411.

The product of its digits is 3936600, while the sum is 55.

The square root of 66999565 is about 8185.3261999752. The cubic root of 66999565 is about 406.1539310509.

The spelling of 66999565 in words is "sixty-six million, nine hundred ninety-nine thousand, five hundred sixty-five".