66351618 has 24 divisors (see below), whose sum is σ = 144233388. Its totient is φ = 22044672.

The previous prime is 66351569. The next prime is 66351683. The reversal of 66351618 is 81615366.

It is a happy number.

66351618 is a `hidden beast` number, since 6 + 6 + 35 + 1 + 618 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 62299449 + 4052169 = 7893^2 + 2013^2 .

It is a super-2 number, since 2×66351618² = 8805074422435848, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 255 + ... + 11522.

Almost surely, 2^66351618 is an apocalyptic number.

66351618 is an abundant number, since it is smaller than the sum of its proper divisors (77881770).

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

66351618 is a wasteful number, since it uses less digits than its factorization.

66351618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12098 (or 12095 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66351618 is about 8145.6502502870. The cubic root of 66351618 is about 404.8403943570.

The spelling of 66351618 in words is "sixty-six million, three hundred fifty-one thousand, six hundred eighteen".