21134719517 has 2 divisors, whose sum is σ = 21134719518. Its totient is φ = 21134719516.

The previous prime is 21134719513. The next prime is 21134719603. The reversal of 21134719517 is 71591743112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13251232996 + 7883486521 = 115114^2 + 88789^2 .

It is a cyclic number.

It is not a de Polignac number, because 21134719517 - 2² = 21134719513 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21134719511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567359758 + 10567359759.

It is an arithmetic number, because the mean of its divisors is an integer number (10567359759).

Almost surely, 2^21134719517 is an apocalyptic number.

It is an amenable number.

21134719517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21134719517 is an equidigital number, since it uses as much as digits as its factorization.

21134719517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52920, while the sum is 41.

The spelling of 21134719517 in words is "twenty-one billion, one hundred thirty-four million, seven hundred nineteen thousand, five hundred seventeen".