20665566998 has 16 divisors (see below), whose sum is σ = 31429458000. Its totient is φ = 10189694592.

The previous prime is 20665566997. The next prime is 20665567001. The reversal of 20665566998 is 89966556602.

It is a self number, because there is not a number n which added to its sum of digits gives 20665566998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20665566997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85703 + ... + 220626.

It is an arithmetic number, because the mean of its divisors is an integer number (1964341125).

Almost surely, 2^20665566998 is an apocalyptic number.

20665566998 is a deficient number, since it is larger than the sum of its proper divisors (10763891002).

20665566998 is a wasteful number, since it uses less digits than its factorization.

20665566998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306799.

The product of its (nonzero) digits is 41990400, while the sum is 62.

The spelling of 20665566998 in words is "twenty billion, six hundred sixty-five million, five hundred sixty-six thousand, nine hundred ninety-eight".