21709491043 has 2 divisors, whose sum is σ = 21709491044. Its totient is φ = 21709491042.

The previous prime is 21709491019. The next prime is 21709491049. The reversal of 21709491043 is 34019490712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21709491043 - 2³³ = 13119556451 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21709490987 and 21709491005.

It is not a weakly prime, because it can be changed into another prime (21709491049) 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, 10854745521 + 10854745522.

It is an arithmetic number, because the mean of its divisors is an integer number (10854745522).

Almost surely, 2^21709491043 is an apocalyptic number.

21709491043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21709491043 is an equidigital number, since it uses as much as digits as its factorization.

21709491043 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 40.

The spelling of 21709491043 in words is "twenty-one billion, seven hundred nine million, four hundred ninety-one thousand, forty-three".