51017581 has 2 divisors, whose sum is σ = 51017582. Its totient is φ = 51017580.

The previous prime is 51017543. The next prime is 51017597. The reversal of 51017581 is 18571015.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49829481 + 1188100 = 7059^2 + 1090^2 .

It is a cyclic number.

It is not a de Polignac number, because 51017581 - 2⁹ = 51017069 is a prime.

It is a super-2 number, since 2×51017581² = 5205587142183122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51017501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25508790 + 25508791.

It is an arithmetic number, because the mean of its divisors is an integer number (25508791).

Almost surely, 2^51017581 is an apocalyptic number.

It is an amenable number.

51017581 is a deficient number, since it is larger than the sum of its proper divisors (1).

51017581 is an equidigital number, since it uses as much as digits as its factorization.

51017581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1400, while the sum is 28.

The square root of 51017581 is about 7142.6592386869. The cubic root of 51017581 is about 370.8855850400.

Adding to 51017581 its reverse (18571015), we get a palindrome (69588596).

The spelling of 51017581 in words is "fifty-one million, seventeen thousand, five hundred eighty-one".