21766755173 has 2 divisors, whose sum is σ = 21766755174. Its totient is φ = 21766755172.

The previous prime is 21766755163. The next prime is 21766755191. The reversal of 21766755173 is 37155766712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21181018369 + 585736804 = 145537^2 + 24202^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21766755173 is a prime.

It is a super-2 number, since 2×21766755173² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21766755163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10883377586 + 10883377587.

It is an arithmetic number, because the mean of its divisors is an integer number (10883377587).

Almost surely, 2^21766755173 is an apocalyptic number.

It is an amenable number.

21766755173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21766755173 is an equidigital number, since it uses as much as digits as its factorization.

21766755173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1852200, while the sum is 50.

The spelling of 21766755173 in words is "twenty-one billion, seven hundred sixty-six million, seven hundred fifty-five thousand, one hundred seventy-three".