50821801661 has 2 divisors, whose sum is σ = 50821801662. Its totient is φ = 50821801660.

The previous prime is 50821801643. The next prime is 50821801669. The reversal of 50821801661 is 16610812805.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33903856900 + 16917944761 = 184130^2 + 130069^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-50821801661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (50821801669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25410900830 + 25410900831.

It is an arithmetic number, because the mean of its divisors is an integer number (25410900831).

Almost surely, 2^50821801661 is an apocalyptic number.

It is an amenable number.

50821801661 is a deficient number, since it is larger than the sum of its proper divisors (1).

50821801661 is an equidigital number, since it uses as much as digits as its factorization.

50821801661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23040, while the sum is 38.

The spelling of 50821801661 in words is "fifty billion, eight hundred twenty-one million, eight hundred one thousand, six hundred sixty-one".