21164657573 has 2 divisors, whose sum is σ = 21164657574. Its totient is φ = 21164657572.

The previous prime is 21164657557. The next prime is 21164657581. The reversal of 21164657573 is 37575646112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21124296964 + 40360609 = 145342^2 + 6353^2 .

It is a cyclic number.

It is not a de Polignac number, because 21164657573 - 2⁴ = 21164657557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21164657543) 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, 10582328786 + 10582328787.

It is an arithmetic number, because the mean of its divisors is an integer number (10582328787).

Almost surely, 2^21164657573 is an apocalyptic number.

It is an amenable number.

21164657573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21164657573 is an equidigital number, since it uses as much as digits as its factorization.

21164657573 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1058400, while the sum is 47.

The spelling of 21164657573 in words is "twenty-one billion, one hundred sixty-four million, six hundred fifty-seven thousand, five hundred seventy-three".