51016781 has 2 divisors, whose sum is σ = 51016782. Its totient is φ = 51016780.

The previous prime is 51016759. The next prime is 51016787. The reversal of 51016781 is 18761015.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32604100 + 18412681 = 5710^2 + 4291^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51016781 is a prime.

It is a super-2 number, since 2×51016781² = 5205423887203922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51016787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25508390 + 25508391.

It is an arithmetic number, because the mean of its divisors is an integer number (25508391).

Almost surely, 2^51016781 is an apocalyptic number.

It is an amenable number.

51016781 is a deficient number, since it is larger than the sum of its proper divisors (1).

51016781 is an equidigital number, since it uses as much as digits as its factorization.

51016781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 29.

The square root of 51016781 is about 7142.6032369158. The cubic root of 51016781 is about 370.8836464271.

Adding to 51016781 its reverse (18761015), we get a palindrome (69777796).

The spelling of 51016781 in words is "fifty-one million, sixteen thousand, seven hundred eighty-one".