21076457789 has 2 divisors, whose sum is σ = 21076457790. Its totient is φ = 21076457788.

The previous prime is 21076457777. The next prime is 21076457791. The reversal of 21076457789 is 98775467012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19688299225 + 1388158564 = 140315^2 + 37258^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21076457789 is a prime.

It is a Sophie Germain prime.

Together with 21076457791, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21076457719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10538228894 + 10538228895.

It is an arithmetic number, because the mean of its divisors is an integer number (10538228895).

Almost surely, 2^21076457789 is an apocalyptic number.

It is an amenable number.

21076457789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21076457789 is an equidigital number, since it uses as much as digits as its factorization.

21076457789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5927040, while the sum is 56.

The spelling of 21076457789 in words is "twenty-one billion, seventy-six million, four hundred fifty-seven thousand, seven hundred eighty-nine".