66666669 has 4 divisors (see below), whose sum is σ = 88888896. Its totient is φ = 44444444.

The previous prime is 66666667. The next prime is 66666683. The reversal of 66666669 is 96666666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66666669 - 2¹ = 66666667 is a prime.

It is a super-2 number, since 2×66666669² = 8888889511111122, which contains 22 as substring.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666667) 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, 11111109 + ... + 11111114.

It is an arithmetic number, because the mean of its divisors is an integer number (22222224).

Almost surely, 2^66666669 is an apocalyptic number.

It is an amenable number.

66666669 is a deficient number, since it is larger than the sum of its proper divisors (22222227).

66666669 is a wasteful number, since it uses less digits than its factorization.

66666669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22222226.

The product of its digits is 2519424, while the sum is 51.

The square root of 66666669 is about 8164.9659521642. The cubic root of 66666669 is about 405.4801377688.

It can be divided in two parts, 666666 and 69, that multiplied together give a palindrome (45999954).

The spelling of 66666669 in words is "sixty-six million, six hundred sixty-six thousand, six hundred sixty-nine".