66531918 has 8 divisors (see below), whose sum is σ = 133063848. Its totient is φ = 22177304.

The previous prime is 66531917. The next prime is 66531929. The reversal of 66531918 is 81913566.

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

66531918 is an admirable number.

It is a super-2 number, since 2×66531918² = 8852992225517448, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66531911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5544321 + ... + 5544332.

It is an arithmetic number, because the mean of its divisors is an integer number (16632981).

Almost surely, 2^66531918 is an apocalyptic number.

66531918 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66531918 is a wasteful number, since it uses less digits than its factorization.

66531918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11088658.

The product of its digits is 38880, while the sum is 39.

The square root of 66531918 is about 8156.7099985227. The cubic root of 66531918 is about 405.2067592352.

The spelling of 66531918 in words is "sixty-six million, five hundred thirty-one thousand, nine hundred eighteen".