21208496723 has 2 divisors, whose sum is σ = 21208496724. Its totient is φ = 21208496722.

The previous prime is 21208496713. The next prime is 21208496759. The reversal of 21208496723 is 32769480212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21208496723 - 2¹⁰ = 21208495699 is a prime.

It is not a weakly prime, because it can be changed into another prime (21208496713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10604248361 + 10604248362.

It is an arithmetic number, because the mean of its divisors is an integer number (10604248362).

Almost surely, 2^21208496723 is an apocalyptic number.

21208496723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21208496723 is an equidigital number, since it uses as much as digits as its factorization.

21208496723 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 44.

The spelling of 21208496723 in words is "twenty-one billion, two hundred eight million, four hundred ninety-six thousand, seven hundred twenty-three".