20361221689 has 2 divisors, whose sum is σ = 20361221690. Its totient is φ = 20361221688.

The previous prime is 20361221653. The next prime is 20361221729. The reversal of 20361221689 is 98612216302.

It is an a-pointer prime, because the next prime (20361221729) can be obtained adding 20361221689 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20311095289 + 50126400 = 142517^2 + 7080^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20361221689 is a prime.

It is not a weakly prime, because it can be changed into another prime (20361221189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10180610844 + 10180610845.

It is an arithmetic number, because the mean of its divisors is an integer number (10180610845).

Almost surely, 2^20361221689 is an apocalyptic number.

It is an amenable number.

20361221689 is a deficient number, since it is larger than the sum of its proper divisors (1).

20361221689 is an equidigital number, since it uses as much as digits as its factorization.

20361221689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 40.

The spelling of 20361221689 in words is "twenty billion, three hundred sixty-one million, two hundred twenty-one thousand, six hundred eighty-nine".