21675455261 has 2 divisors, whose sum is σ = 21675455262. Its totient is φ = 21675455260.

The previous prime is 21675455251. The next prime is 21675455309. The reversal of 21675455261 is 16255457612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13194887161 + 8480568100 = 114869^2 + 92090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21675455261 - 2¹⁰ = 21675454237 is a prime.

It is a super-2 number, since 2×21675455261² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21675455251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10837727630 + 10837727631.

It is an arithmetic number, because the mean of its divisors is an integer number (10837727631).

Almost surely, 2^21675455261 is an apocalyptic number.

It is an amenable number.

21675455261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21675455261 is an equidigital number, since it uses as much as digits as its factorization.

21675455261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504000, while the sum is 44.

The spelling of 21675455261 in words is "twenty-one billion, six hundred seventy-five million, four hundred fifty-five thousand, two hundred sixty-one".