21761335213 has 2 divisors, whose sum is σ = 21761335214. Its totient is φ = 21761335212.

The previous prime is 21761335187. The next prime is 21761335223. The reversal of 21761335213 is 31253316712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21451117444 + 310217769 = 146462^2 + 17613^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21761335213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21761335223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10880667606 + 10880667607.

It is an arithmetic number, because the mean of its divisors is an integer number (10880667607).

Almost surely, 2^21761335213 is an apocalyptic number.

It is an amenable number.

21761335213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21761335213 is an equidigital number, since it uses as much as digits as its factorization.

21761335213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 34.

The spelling of 21761335213 in words is "twenty-one billion, seven hundred sixty-one million, three hundred thirty-five thousand, two hundred thirteen".