66791817 has 16 divisors (see below), whose sum is σ = 99550080. Its totient is φ = 44258256.

The previous prime is 66791797. The next prime is 66791869. The reversal of 66791817 is 71819766.

It is not a de Polignac number, because 66791817 - 2¹⁰ = 66790793 is a prime.

It is a super-2 number, since 2×66791817² = 8922293636322978, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66791017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2898 + ... + 11915.

It is an arithmetic number, because the mean of its divisors is an integer number (6221880).

Almost surely, 2^66791817 is an apocalyptic number.

It is an amenable number.

66791817 is a deficient number, since it is larger than the sum of its proper divisors (32758263).

66791817 is a wasteful number, since it uses less digits than its factorization.

66791817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14989 (or 14983 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 66791817 is about 8172.6260773389. The cubic root of 66791817 is about 405.7337043008.

The spelling of 66791817 in words is "sixty-six million, seven hundred ninety-one thousand, eight hundred seventeen".