51661371361 has 2 divisors, whose sum is σ = 51661371362. Its totient is φ = 51661371360.

The previous prime is 51661371331. The next prime is 51661371401. The reversal of 51661371361 is 16317316615.

51661371361 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (51661371401) can be obtained adding 51661371361 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51594851025 + 66520336 = 227145^2 + 8156^2 .

It is a cyclic number.

It is not a de Polignac number, because 51661371361 - 2¹¹ = 51661369313 is a prime.

It is not a weakly prime, because it can be changed into another prime (51661371331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25830685680 + 25830685681.

It is an arithmetic number, because the mean of its divisors is an integer number (25830685681).

Almost surely, 2^51661371361 is an apocalyptic number.

It is an amenable number.

51661371361 is a deficient number, since it is larger than the sum of its proper divisors (1).

51661371361 is an equidigital number, since it uses as much as digits as its factorization.

51661371361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68040, while the sum is 40.

Adding to 51661371361 its reverse (16317316615), we get a palindrome (67978687976).

The spelling of 51661371361 in words is "fifty-one billion, six hundred sixty-one million, three hundred seventy-one thousand, three hundred sixty-one".