66818531 has 8 divisors (see below), whose sum is σ = 73316880. Its totient is φ = 60514272.

The previous prime is 66818527. The next prime is 66818539. The reversal of 66818531 is 13581866.

It is a happy number.

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

It is not a de Polignac number, because 66818531 - 2² = 66818527 is a prime.

It is a super-2 number, since 2×66818531² = 8929432169995922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66818539) 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 7 ways as a sum of consecutive naturals, for example, 47801 + ... + 49178.

It is an arithmetic number, because the mean of its divisors is an integer number (9164610).

Almost surely, 2^66818531 is an apocalyptic number.

66818531 is a deficient number, since it is larger than the sum of its proper divisors (6498349).

66818531 is a wasteful number, since it uses less digits than its factorization.

66818531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97045.

The product of its digits is 34560, while the sum is 38.

The square root of 66818531 is about 8174.2602723427. The cubic root of 66818531 is about 405.7877893966.

The spelling of 66818531 in words is "sixty-six million, eight hundred eighteen thousand, five hundred thirty-one".