669178829861 has 4 divisors (see below), whose sum is σ = 669279118092. Its totient is φ = 669078541632.

The previous prime is 669178829807. The next prime is 669178829909. The reversal of 669178829861 is 168928871966.

669178829861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 168928871966 = 2 ⋅84464435983.

It can be written as a sum of positive squares in 2 ways, for example, as 62797352836 + 606381477025 = 250594^2 + 778705^2 .

It is a cyclic number.

It is not a de Polignac number, because 669178829861 - 2⁶ = 669178829797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669178826861) 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, 50134106 + ... + 50147451.

It is an arithmetic number, because the mean of its divisors is an integer number (167319779523).

Almost surely, 2^669178829861 is an apocalyptic number.

It is an amenable number.

669178829861 is a deficient number, since it is larger than the sum of its proper divisors (100288231).

669178829861 is a wasteful number, since it uses less digits than its factorization.

669178829861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100288230.

The product of its digits is 125411328, while the sum is 71.

The spelling of 669178829861 in words is "six hundred sixty-nine billion, one hundred seventy-eight million, eight hundred twenty-nine thousand, eight hundred sixty-one".