21426646751261 has 2 divisors, whose sum is σ = 21426646751262. Its totient is φ = 21426646751260.

The previous prime is 21426646751221. The next prime is 21426646751287. The reversal of 21426646751261 is 16215764662412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17847667622500 + 3578979128761 = 4224650^2 + 1891819^2 .

It is a cyclic number.

It is not a de Polignac number, because 21426646751261 - 2³⁰ = 21425573009437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21426646751221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10713323375630 + 10713323375631.

It is an arithmetic number, because the mean of its divisors is an integer number (10713323375631).

Almost surely, 2^{21426646751261} is an apocalyptic number.

It is an amenable number.

21426646751261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21426646751261 is an equidigital number, since it uses as much as digits as its factorization.

21426646751261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5806080, while the sum is 53.

The spelling of 21426646751261 in words is "twenty-one trillion, four hundred twenty-six billion, six hundred forty-six million, seven hundred fifty-one thousand, two hundred sixty-one".