21659447388353 has 2 divisors, whose sum is σ = 21659447388354. Its totient is φ = 21659447388352.

The previous prime is 21659447388281. The next prime is 21659447388373. The reversal of 21659447388353 is 35388374495612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19481780509489 + 2177666878864 = 4413817^2 + 1475692^2 .

It is a cyclic number.

It is not a de Polignac number, because 21659447388353 - 2¹⁸ = 21659447126209 is a prime.

It is a super-2 number, since 2×21659447388353² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21659447388373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10829723694176 + 10829723694177.

It is an arithmetic number, because the mean of its divisors is an integer number (10829723694177).

Almost surely, 2^{21659447388353} is an apocalyptic number.

It is an amenable number.

21659447388353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21659447388353 is an equidigital number, since it uses as much as digits as its factorization.

21659447388353 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 522547200, while the sum is 68.

The spelling of 21659447388353 in words is "twenty-one trillion, six hundred fifty-nine billion, four hundred forty-seven million, three hundred eighty-eight thousand, three hundred fifty-three".