21655404442249 has 2 divisors, whose sum is σ = 21655404442250. Its totient is φ = 21655404442248.

The previous prime is 21655404442229. The next prime is 21655404442277. The reversal of 21655404442249 is 94224440455612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19120723925625 + 2534680516624 = 4372725^2 + 1592068^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21655404442249 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21655404442196 and 21655404442205.

It is not a weakly prime, because it can be changed into another prime (21655404442229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10827702221124 + 10827702221125.

It is an arithmetic number, because the mean of its divisors is an integer number (10827702221125).

Almost surely, 2^{21655404442249} is an apocalyptic number.

It is an amenable number.

21655404442249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21655404442249 is an equidigital number, since it uses as much as digits as its factorization.

21655404442249 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11059200, while the sum is 52.

The spelling of 21655404442249 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred four million, four hundred forty-two thousand, two hundred forty-nine".