21620536220417 has 2 divisors, whose sum is σ = 21620536220418. Its totient is φ = 21620536220416.

The previous prime is 21620536220383. The next prime is 21620536220429. The reversal of 21620536220417 is 71402263502612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19944834449296 + 1675701771121 = 4465964^2 + 1294489^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620536220417 - 2⁸ = 21620536220161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21620536220467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810268110208 + 10810268110209.

It is an arithmetic number, because the mean of its divisors is an integer number (10810268110209).

Almost surely, 2^{21620536220417} is an apocalyptic number.

It is an amenable number.

21620536220417 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620536220417 is an equidigital number, since it uses as much as digits as its factorization.

21620536220417 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 21620536220417 in words is "twenty-one trillion, six hundred twenty billion, five hundred thirty-six million, two hundred twenty thousand, four hundred seventeen".