9421727617661 has 2 divisors, whose sum is σ = 9421727617662. Its totient is φ = 9421727617660.

The previous prime is 9421727617637. The next prime is 9421727617663. The reversal of 9421727617661 is 1667167271249.

9421727617661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8632284705625 + 789442912036 = 2938075^2 + 888506^2 .

It is an emirp because it is prime and its reverse (1667167271249) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9421727617661 is a prime.

It is a super-2 number, since 2×9421727617661² (a number of 27 digits) contains 22 as substring.

Together with 9421727617663, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 9421727617661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9421727617663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4710863808830 + 4710863808831.

It is an arithmetic number, because the mean of its divisors is an integer number (4710863808831).

Almost surely, 2^{9421727617661} is an apocalyptic number.

It is an amenable number.

9421727617661 is a deficient number, since it is larger than the sum of its proper divisors (1).

9421727617661 is an equidigital number, since it uses as much as digits as its factorization.

9421727617661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10668672, while the sum is 59.

The spelling of 9421727617661 in words is "nine trillion, four hundred twenty-one billion, seven hundred twenty-seven million, six hundred seventeen thousand, six hundred sixty-one".