51143781 has 32 divisors (see below), whose sum is σ = 75841920. Its totient is φ = 30461184.

The previous prime is 51143777. The next prime is 51143783. The reversal of 51143781 is 18734115.

It is not a de Polignac number, because 51143781 - 2² = 51143777 is a prime.

It is a super-2 number, since 2×51143781² = 5231372669951922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51143783) 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 31 ways as a sum of consecutive naturals, for example, 225190 + ... + 225416.

It is an arithmetic number, because the mean of its divisors is an integer number (2370060).

Almost surely, 2^51143781 is an apocalyptic number.

It is an amenable number.

51143781 is a deficient number, since it is larger than the sum of its proper divisors (24698139).

51143781 is a wasteful number, since it uses less digits than its factorization.

51143781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405.

The product of its digits is 3360, while the sum is 30.

The square root of 51143781 is about 7151.4880269773. The cubic root of 51143781 is about 371.1911478091.

Adding to 51143781 its reverse (18734115), we get a palindrome (69877896).

The spelling of 51143781 in words is "fifty-one million, one hundred forty-three thousand, seven hundred eighty-one".