21717343537 has 2 divisors, whose sum is σ = 21717343538. Its totient is φ = 21717343536.

The previous prime is 21717343523. The next prime is 21717343579. The reversal of 21717343537 is 73534371712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20155196961 + 1562146576 = 141969^2 + 39524^2 .

It is a cyclic number.

It is not a de Polignac number, because 21717343537 - 2⁷ = 21717343409 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21717343493 and 21717343502.

It is not a weakly prime, because it can be changed into another prime (21717343597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10858671768 + 10858671769.

It is an arithmetic number, because the mean of its divisors is an integer number (10858671769).

Almost surely, 2^21717343537 is an apocalyptic number.

It is an amenable number.

21717343537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21717343537 is an equidigital number, since it uses as much as digits as its factorization.

21717343537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 370440, while the sum is 43.

The spelling of 21717343537 in words is "twenty-one billion, seven hundred seventeen million, three hundred forty-three thousand, five hundred thirty-seven".