21603217772161 has 2 divisors, whose sum is σ = 21603217772162. Its totient is φ = 21603217772160.

The previous prime is 21603217772131. The next prime is 21603217772219. The reversal of 21603217772161 is 16127771230612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21591644315761 + 11573456400 = 4646681^2 + 107580^2 .

It is a cyclic number.

It is not a de Polignac number, because 21603217772161 - 2¹³ = 21603217763969 is a prime.

It is a super-2 number, since 2×21603217772161² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21603217772131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801608886080 + 10801608886081.

It is an arithmetic number, because the mean of its divisors is an integer number (10801608886081).

Almost surely, 2^{21603217772161} is an apocalyptic number.

It is an amenable number.

21603217772161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21603217772161 is an equidigital number, since it uses as much as digits as its factorization.

21603217772161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 296352, while the sum is 46.

The spelling of 21603217772161 in words is "twenty-one trillion, six hundred three billion, two hundred seventeen million, seven hundred seventy-two thousand, one hundred sixty-one".