20210101209989 has 2 divisors, whose sum is σ = 20210101209990. Its totient is φ = 20210101209988.

The previous prime is 20210101209959. The next prime is 20210101210001. The reversal of 20210101209989 is 98990210101202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18586592021089 + 1623509188900 = 4311217^2 + 1274170^2 .

It is a cyclic number.

It is not a de Polignac number, because 20210101209989 - 2²⁰ = 20210100161413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20210101209959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105050604994 + 10105050604995.

It is an arithmetic number, because the mean of its divisors is an integer number (10105050604995).

Almost surely, 2^{20210101209989} is an apocalyptic number.

It is an amenable number.

20210101209989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210101209989 is an equidigital number, since it uses as much as digits as its factorization.

20210101209989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 44.

The spelling of 20210101209989 in words is "twenty trillion, two hundred ten billion, one hundred one million, two hundred nine thousand, nine hundred eighty-nine".