20210021389 has 2 divisors, whose sum is σ = 20210021390. Its totient is φ = 20210021388.

The previous prime is 20210021387. The next prime is 20210021417. The reversal of 20210021389 is 98312001202.

It is an a-pointer prime, because the next prime (20210021417) can be obtained adding 20210021389 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12708729289 + 7501292100 = 112733^2 + 86610^2 .

It is a cyclic number.

It is not a de Polignac number, because 20210021389 - 2¹ = 20210021387 is a prime.

Together with 20210021387, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20210021387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105010694 + 10105010695.

It is an arithmetic number, because the mean of its divisors is an integer number (10105010695).

Almost surely, 2^20210021389 is an apocalyptic number.

It is an amenable number.

20210021389 is a deficient number, since it is larger than the sum of its proper divisors (1).

20210021389 is an equidigital number, since it uses as much as digits as its factorization.

20210021389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The spelling of 20210021389 in words is "twenty billion, two hundred ten million, twenty-one thousand, three hundred eighty-nine".