51032781 has 8 divisors (see below), whose sum is σ = 75604160. Its totient is φ = 34021836.

The previous prime is 51032749. The next prime is 51032809. The reversal of 51032781 is 18723015.

51032781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51032781 - 2⁵ = 51032749 is a prime.

It is a super-2 number, since 2×51032781² = 5208689473187922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 1890103 = 51032781 / (5 + 1 + 0 + 3 + 2 + 7 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51032711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 945025 + ... + 945078.

It is an arithmetic number, because the mean of its divisors is an integer number (9450520).

Almost surely, 2^51032781 is an apocalyptic number.

It is an amenable number.

51032781 is a deficient number, since it is larger than the sum of its proper divisors (24571379).

51032781 is a wasteful number, since it uses less digits than its factorization.

51032781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1890112 (or 1890106 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 51032781 is about 7143.7231889261. The cubic root of 51032781 is about 370.9224148348.

Adding to 51032781 its reverse (18723015), we get a palindrome (69755796).

The spelling of 51032781 in words is "fifty-one million, thirty-two thousand, seven hundred eighty-one".