51249581 has 2 divisors, whose sum is σ = 51249582. Its totient is φ = 51249580.

The previous prime is 51249571. The next prime is 51249587. The reversal of 51249581 is 18594215.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39062500 + 12187081 = 6250^2 + 3491^2 .

It is a cyclic number.

It is not a de Polignac number, because 51249581 - 2²² = 47055277 is a prime.

It is a super-2 number, since 2×51249581² = 5253039105351122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51249587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25624790 + 25624791.

It is an arithmetic number, because the mean of its divisors is an integer number (25624791).

Almost surely, 2^51249581 is an apocalyptic number.

It is an amenable number.

51249581 is a deficient number, since it is larger than the sum of its proper divisors (1).

51249581 is an equidigital number, since it uses as much as digits as its factorization.

51249581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 35.

The square root of 51249581 is about 7158.8812673490. The cubic root of 51249581 is about 371.4469297984.

The spelling of 51249581 in words is "fifty-one million, two hundred forty-nine thousand, five hundred eighty-one".