21034121389 has 2 divisors, whose sum is σ = 21034121390. Its totient is φ = 21034121388.

The previous prime is 21034121387. The next prime is 21034121417. The reversal of 21034121389 is 98312143012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19389170025 + 1644951364 = 139245^2 + 40558^2 .

It is a cyclic number.

It is not a de Polignac number, because 21034121389 - 2¹ = 21034121387 is a prime.

Together with 21034121387, 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 (21034121387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10517060694 + 10517060695.

It is an arithmetic number, because the mean of its divisors is an integer number (10517060695).

Almost surely, 2^21034121389 is an apocalyptic number.

It is an amenable number.

21034121389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21034121389 is an equidigital number, since it uses as much as digits as its factorization.

21034121389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 34.

The spelling of 21034121389 in words is "twenty-one billion, thirty-four million, one hundred twenty-one thousand, three hundred eighty-nine".