20668734646 has 16 divisors (see below), whose sum is σ = 35459850240. Its totient is φ = 8851095720.

The previous prime is 20668734631. The next prime is 20668734649. The reversal of 20668734646 is 64643786602.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 20668734593 and 20668734602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20668734649) 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 7 ways as a sum of consecutive naturals, for example, 559240 + ... + 595051.

It is an arithmetic number, because the mean of its divisors is an integer number (2216240640).

Almost surely, 2^20668734646 is an apocalyptic number.

20668734646 is a deficient number, since it is larger than the sum of its proper divisors (14791115594).

20668734646 is a wasteful number, since it uses less digits than its factorization.

20668734646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155579.

The product of its (nonzero) digits is 6967296, while the sum is 52.

The spelling of 20668734646 in words is "twenty billion, six hundred sixty-eight million, seven hundred thirty-four thousand, six hundred forty-six".