20889796661 has 2 divisors, whose sum is σ = 20889796662. Its totient is φ = 20889796660.

The previous prime is 20889796657. The next prime is 20889796691. The reversal of 20889796661 is 16669798802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20183884900 + 705911761 = 142070^2 + 26569^2 .

It is a cyclic number.

It is not a de Polignac number, because 20889796661 - 2² = 20889796657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20889796594 and 20889796603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20889796691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10444898330 + 10444898331.

It is an arithmetic number, because the mean of its divisors is an integer number (10444898331).

Almost surely, 2^20889796661 is an apocalyptic number.

It is an amenable number.

20889796661 is a deficient number, since it is larger than the sum of its proper divisors (1).

20889796661 is an equidigital number, since it uses as much as digits as its factorization.

20889796661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15676416, while the sum is 62.

The spelling of 20889796661 in words is "twenty billion, eight hundred eighty-nine million, seven hundred ninety-six thousand, six hundred sixty-one".