21340008709 has 2 divisors, whose sum is σ = 21340008710. Its totient is φ = 21340008708.

The previous prime is 21340008689. The next prime is 21340008757. The reversal of 21340008709 is 90780004312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20823355809 + 516652900 = 144303^2 + 22730^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21340008709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21340008799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10670004354 + 10670004355.

It is an arithmetic number, because the mean of its divisors is an integer number (10670004355).

Almost surely, 2^21340008709 is an apocalyptic number.

It is an amenable number.

21340008709 is a deficient number, since it is larger than the sum of its proper divisors (1).

21340008709 is an equidigital number, since it uses as much as digits as its factorization.

21340008709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 34.

The spelling of 21340008709 in words is "twenty-one billion, three hundred forty million, eight thousand, seven hundred nine".