21661465735369 has 2 divisors, whose sum is σ = 21661465735370. Its totient is φ = 21661465735368.

The previous prime is 21661465735237. The next prime is 21661465735421. The reversal of 21661465735369 is 96353756416612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17419563005625 + 4241902729744 = 4173675^2 + 2059588^2 .

It is a cyclic number.

It is not a de Polignac number, because 21661465735369 - 2³⁷ = 21524026781897 is a prime.

It is a super-2 number, since 2×21661465735369² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21661465735369.

It is not a weakly prime, because it can be changed into another prime (21661465735769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10830732867684 + 10830732867685.

It is an arithmetic number, because the mean of its divisors is an integer number (10830732867685).

Almost surely, 2^{21661465735369} is an apocalyptic number.

It is an amenable number.

21661465735369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21661465735369 is an equidigital number, since it uses as much as digits as its factorization.

21661465735369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 146966400, while the sum is 64.

The spelling of 21661465735369 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred sixty-five million, seven hundred thirty-five thousand, three hundred sixty-nine".