21339794393 has 4 divisors (see below), whose sum is σ = 21551079588. Its totient is φ = 21128509200.

The previous prime is 21339794383. The next prime is 21339794407. The reversal of 21339794393 is 39349793312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14731405129 + 6608389264 = 121373^2 + 81292^2 .

It is a cyclic number.

It is not a de Polignac number, because 21339794393 - 2⁸ = 21339794137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21339794383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105642446 + ... + 105642647.

It is an arithmetic number, because the mean of its divisors is an integer number (5387769897).

Almost surely, 2^21339794393 is an apocalyptic number.

It is an amenable number.

21339794393 is a deficient number, since it is larger than the sum of its proper divisors (211285195).

21339794393 is a wasteful number, since it uses less digits than its factorization.

21339794393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211285194.

The product of its digits is 3306744, while the sum is 53.

The spelling of 21339794393 in words is "twenty-one billion, three hundred thirty-nine million, seven hundred ninety-four thousand, three hundred ninety-three".