66388550 has 24 divisors (see below), whose sum is σ = 125228592. Its totient is φ = 26180000.

The previous prime is 66388541. The next prime is 66388561. The reversal of 66388550 is 5588366.

It is a super-2 number, since 2×66388550² = 8814879142205000, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 66388498 and 66388507.

It is a congruent 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, 5801 + ... + 12900.

It is an arithmetic number, because the mean of its divisors is an integer number (5217858).

Almost surely, 2^66388550 is an apocalyptic number.

66388550 is a deficient number, since it is larger than the sum of its proper divisors (58840042).

66388550 is a wasteful number, since it uses less digits than its factorization.

66388550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18784 (or 18779 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 41.

The square root of 66388550 is about 8147.9169117020. The cubic root of 66388550 is about 404.9154932151.

The spelling of 66388550 in words is "sixty-six million, three hundred eighty-eight thousand, five hundred fifty".