21444633066661 has 6 divisors (see below), whose sum is σ = 24945797649030. Its totient is φ = 18381114057096.

The previous prime is 21444633066643. The next prime is 21444633066677. The reversal of 21444633066661 is 16666033644412.

It can be written as a sum of positive squares in only one way, i.e., 20387879906436 + 1056753160225 = 4515294^2 + 1027985^2 .

It is not a de Polignac number, because 21444633066661 - 2⁹ = 21444633066149 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21444633066599 and 21444633066608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444633066611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 218822786346 + ... + 218822786443.

It is an arithmetic number, because the mean of its divisors is an integer number (4157632941505).

Almost surely, 2^{21444633066661} is an apocalyptic number.

It is an amenable number.

21444633066661 is a deficient number, since it is larger than the sum of its proper divisors (3501164582369).

21444633066661 is an equidigital number, since it uses as much as digits as its factorization.

21444633066661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437645572803 (or 437645572796 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 52.

The spelling of 21444633066661 in words is "twenty-one trillion, four hundred forty-four billion, six hundred thirty-three million, sixty-six thousand, six hundred sixty-one".