20668734635 has 4 divisors (see below), whose sum is σ = 24802481568. Its totient is φ = 16534987704.

The previous prime is 20668734631. The next prime is 20668734649. The reversal of 20668734635 is 53643786602.

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 20668734635 - 2² = 20668734631 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20668734631) 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, 2066873459 + ... + 2066873468.

It is an arithmetic number, because the mean of its divisors is an integer number (6200620392).

Almost surely, 2^20668734635 is an apocalyptic number.

20668734635 is a deficient number, since it is larger than the sum of its proper divisors (4133746933).

20668734635 is an equidigital number, since it uses as much as digits as its factorization.

20668734635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4133746932.

The product of its (nonzero) digits is 4354560, while the sum is 50.

The spelling of 20668734635 in words is "twenty billion, six hundred sixty-eight million, seven hundred thirty-four thousand, six hundred thirty-five".