20669215477 has 4 divisors (see below), whose sum is σ = 20712366720. Its totient is φ = 20626064236.

The previous prime is 20669215459. The next prime is 20669215513. The reversal of 20669215477 is 77451296602.

It is a happy number.

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 20669215477 - 2¹¹ = 20669213429 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20669215477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20669215277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21574903 + ... + 21575860.

It is an arithmetic number, because the mean of its divisors is an integer number (5178091680).

Almost surely, 2^20669215477 is an apocalyptic number.

It is an amenable number.

20669215477 is a deficient number, since it is larger than the sum of its proper divisors (43151243).

20669215477 is an equidigital number, since it uses as much as digits as its factorization.

20669215477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43151242.

The product of its (nonzero) digits is 1270080, while the sum is 49.

The spelling of 20669215477 in words is "twenty billion, six hundred sixty-nine million, two hundred fifteen thousand, four hundred seventy-seven".