51125781 has 16 divisors (see below), whose sum is σ = 78217344. Its totient is φ = 29097984.

The previous prime is 51125779. The next prime is 51125807. The reversal of 51125781 is 18752115.

It is not a de Polignac number, because 51125781 - 2¹ = 51125779 is a prime.

It is a super-2 number, since 2×51125781² = 5227690965719922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51125741) 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 in 15 ways as a sum of consecutive naturals, for example, 661 + ... + 10133.

It is an arithmetic number, because the mean of its divisors is an integer number (4888584).

Almost surely, 2^51125781 is an apocalyptic number.

It is an amenable number.

51125781 is a deficient number, since it is larger than the sum of its proper divisors (27091563).

51125781 is a wasteful number, since it uses less digits than its factorization.

51125781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9740.

The product of its digits is 2800, while the sum is 30.

The square root of 51125781 is about 7150.2294368782. The cubic root of 51125781 is about 371.1475959212.

Adding to 51125781 its reverse (18752115), we get a palindrome (69877896).

The spelling of 51125781 in words is "fifty-one million, one hundred twenty-five thousand, seven hundred eighty-one".