21375963989 has 2 divisors, whose sum is σ = 21375963990. Its totient is φ = 21375963988.

The previous prime is 21375963941. The next prime is 21375963991. The reversal of 21375963989 is 98936957312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12430020100 + 8945943889 = 111490^2 + 94583^2 .

It is a cyclic number.

It is not a de Polignac number, because 21375963989 - 2¹² = 21375959893 is a prime.

Together with 21375963991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21375963919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687981994 + 10687981995.

It is an arithmetic number, because the mean of its divisors is an integer number (10687981995).

Almost surely, 2^21375963989 is an apocalyptic number.

It is an amenable number.

21375963989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375963989 is an equidigital number, since it uses as much as digits as its factorization.

21375963989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22044960, while the sum is 62.

The spelling of 21375963989 in words is "twenty-one billion, three hundred seventy-five million, nine hundred sixty-three thousand, nine hundred eighty-nine".