21445767437641 has 2 divisors, whose sum is σ = 21445767437642. Its totient is φ = 21445767437640.

The previous prime is 21445767437603. The next prime is 21445767437663. The reversal of 21445767437641 is 14673476754412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17183545252416 + 4262222185225 = 4145304^2 + 2064515^2 .

It is a cyclic number.

It is not a de Polignac number, because 21445767437641 - 2²⁹ = 21445230566729 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21445767437641.

It is not a weakly prime, because it can be changed into another prime (21445767432641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722883718820 + 10722883718821.

It is an arithmetic number, because the mean of its divisors is an integer number (10722883718821).

Almost surely, 2^{21445767437641} is an apocalyptic number.

It is an amenable number.

21445767437641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21445767437641 is an equidigital number, since it uses as much as digits as its factorization.

21445767437641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 94832640, while the sum is 61.

The spelling of 21445767437641 in words is "twenty-one trillion, four hundred forty-five billion, seven hundred sixty-seven million, four hundred thirty-seven thousand, six hundred forty-one".