55518666 has 64 divisors (see below), whose sum is σ = 132192000. Its totient is φ = 15532608.

The previous prime is 55518647. The next prime is 55518667. The reversal of 55518666 is 66681555.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (55518667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 108820 + ... + 109328.

It is an arithmetic number, because the mean of its divisors is an integer number (2065500).

Almost surely, 2^55518666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55518666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66096000).

55518666 is an abundant number, since it is smaller than the sum of its proper divisors (76673334).

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

55518666 is a wasteful number, since it uses less digits than its factorization.

55518666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588 (or 574 counting only the distinct ones).

The product of its digits is 216000, while the sum is 42.

The square root of 55518666 is about 7451.0848874510. The cubic root of 55518666 is about 381.4869394850.

The spelling of 55518666 in words is "fifty-five million, five hundred eighteen thousand, six hundred sixty-six".