20649988673 has 4 divisors (see below), whose sum is σ = 20651698608. Its totient is φ = 20648278740.

The previous prime is 20649988663. The next prime is 20649988687. The reversal of 20649988673 is 37688994602.

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 20649988673 - 2¹⁰ = 20649987649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20649988663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 836723 + ... + 861048.

It is an arithmetic number, because the mean of its divisors is an integer number (5162924652).

Almost surely, 2^20649988673 is an apocalyptic number.

It is an amenable number.

20649988673 is a deficient number, since it is larger than the sum of its proper divisors (1709935).

20649988673 is a wasteful number, since it uses less digits than its factorization.

20649988673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1709934.

The product of its (nonzero) digits is 31352832, while the sum is 62.

The spelling of 20649988673 in words is "twenty billion, six hundred forty-nine million, nine hundred eighty-eight thousand, six hundred seventy-three".