51101681 has 2 divisors, whose sum is σ = 51101682. Its totient is φ = 51101680.

The previous prime is 51101663. The next prime is 51101719. The reversal of 51101681 is 18610115.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49561600 + 1540081 = 7040^2 + 1241^2 .

It is a cyclic number.

It is not a de Polignac number, because 51101681 - 2¹⁴ = 51085297 is a prime.

It is a super-2 number, since 2×51101681² = 5222763602051522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51101581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25550840 + 25550841.

It is an arithmetic number, because the mean of its divisors is an integer number (25550841).

Almost surely, 2^51101681 is an apocalyptic number.

It is an amenable number.

51101681 is a deficient number, since it is larger than the sum of its proper divisors (1).

51101681 is an equidigital number, since it uses as much as digits as its factorization.

51101681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 23.

The square root of 51101681 is about 7148.5439776223. The cubic root of 51101681 is about 371.0892687738.

Adding to 51101681 its reverse (18610115), we get a palindrome (69711796).

The spelling of 51101681 in words is "fifty-one million, one hundred one thousand, six hundred eighty-one".