51111581 has 2 divisors, whose sum is σ = 51111582. Its totient is φ = 51111580.

The previous prime is 51111559. The next prime is 51111617. The reversal of 51111581 is 18511115.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45010681 + 6100900 = 6709^2 + 2470^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51111581 is a prime.

It is a super-3 number, since 3×51111581³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51110581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25555790 + 25555791.

It is an arithmetic number, because the mean of its divisors is an integer number (25555791).

Almost surely, 2^51111581 is an apocalyptic number.

It is an amenable number.

51111581 is a deficient number, since it is larger than the sum of its proper divisors (1).

51111581 is an equidigital number, since it uses as much as digits as its factorization.

51111581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 200, while the sum is 23.

The square root of 51111581 is about 7149.2363927905. The cubic root of 51111581 is about 371.1132311072.

Adding to 51111581 its reverse (18511115), we get a palindrome (69622696).

The spelling of 51111581 in words is "fifty-one million, one hundred eleven thousand, five hundred eighty-one".