66668869 has 4 divisors (see below), whose sum is σ = 67280620. Its totient is φ = 66057120.

The previous prime is 66668843. The next prime is 66668873. The reversal of 66668869 is 96886666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 48135844 + 18533025 = 6938^2 + 4305^2 .

It is a cyclic number.

It is not a de Polignac number, because 66668869 - 2¹⁷ = 66537797 is a prime.

It is a super-2 number, since 2×66668869² = 8889476187478322, 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 (66668809) 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, 305712 + ... + 305929.

It is an arithmetic number, because the mean of its divisors is an integer number (16820155).

Almost surely, 2^66668869 is an apocalyptic number.

It is an amenable number.

66668869 is a deficient number, since it is larger than the sum of its proper divisors (611751).

66668869 is a wasteful number, since it uses less digits than its factorization.

66668869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611750.

The product of its digits is 4478976, while the sum is 55.

The square root of 66668869 is about 8165.1006729862. The cubic root of 66668869 is about 405.4845980011.

The spelling of 66668869 in words is "sixty-six million, six hundred sixty-eight thousand, eight hundred sixty-nine".