20101220111989 has 2 divisors, whose sum is σ = 20101220111990. Its totient is φ = 20101220111988.

The previous prime is 20101220111953. The next prime is 20101220112011. The reversal of 20101220111989 is 98911102210102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19998157924900 + 103062187089 = 4471930^2 + 321033^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101220111989 - 2⁴¹ = 17902196856437 is a prime.

It is a super-2 number, since 2×20101220111989² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20101220111909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050610055994 + 10050610055995.

It is an arithmetic number, because the mean of its divisors is an integer number (10050610055995).

Almost surely, 2^{20101220111989} is an apocalyptic number.

It is an amenable number.

20101220111989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101220111989 is an equidigital number, since it uses as much as digits as its factorization.

20101220111989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 37.

The spelling of 20101220111989 in words is "twenty trillion, one hundred one billion, two hundred twenty million, one hundred eleven thousand, nine hundred eighty-nine".