66550111 has 4 divisors (see below), whose sum is σ = 68097832. Its totient is φ = 65002392.

The previous prime is 66550069. The next prime is 66550117. The reversal of 66550111 is 11105566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66550111 - 2¹⁵ = 66517343 is a prime.

It is a super-2 number, since 2×66550111² = 8857834548224642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66550117) 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, 773796 + ... + 773881.

It is an arithmetic number, because the mean of its divisors is an integer number (17024458).

Almost surely, 2^66550111 is an apocalyptic number.

66550111 is a deficient number, since it is larger than the sum of its proper divisors (1547721).

66550111 is a wasteful number, since it uses less digits than its factorization.

66550111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1547720.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 66550111 is about 8157.8251390919. The cubic root of 66550111 is about 405.2436901547.

Adding to 66550111 its reverse (11105566), we get a palindrome (77655677).

The spelling of 66550111 in words is "sixty-six million, five hundred fifty thousand, one hundred eleven".