21306499793 has 2 divisors, whose sum is σ = 21306499794. Its totient is φ = 21306499792.

The previous prime is 21306499757. The next prime is 21306499817. The reversal of 21306499793 is 39799460312.

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., 11502133504 + 9804366289 = 107248^2 + 99017^2 .

It is a cyclic number.

It is not a de Polignac number, because 21306499793 - 2⁸ = 21306499537 is a prime.

It is not a weakly prime, because it can be changed into another prime (21306499693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653249896 + 10653249897.

It is an arithmetic number, because the mean of its divisors is an integer number (10653249897).

Almost surely, 2^21306499793 is an apocalyptic number.

It is an amenable number.

21306499793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21306499793 is an equidigital number, since it uses as much as digits as its factorization.

21306499793 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2204496, while the sum is 53.

The spelling of 21306499793 in words is "twenty-one billion, three hundred six million, four hundred ninety-nine thousand, seven hundred ninety-three".