21454445344861 has 2 divisors, whose sum is σ = 21454445344862. Its totient is φ = 21454445344860.

The previous prime is 21454445344811. The next prime is 21454445344889. The reversal of 21454445344861 is 16844354445412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18802465664761 + 2651979680100 = 4336181^2 + 1628490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21454445344861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21454445344811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727222672430 + 10727222672431.

It is an arithmetic number, because the mean of its divisors is an integer number (10727222672431).

Almost surely, 2^{21454445344861} is an apocalyptic number.

It is an amenable number.

21454445344861 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454445344861 is an equidigital number, since it uses as much as digits as its factorization.

21454445344861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29491200, while the sum is 55.

The spelling of 21454445344861 in words is "twenty-one trillion, four hundred fifty-four billion, four hundred forty-five million, three hundred forty-four thousand, eight hundred sixty-one".