51581081 has 2 divisors, whose sum is σ = 51581082. Its totient is φ = 51581080.

The previous prime is 51581027. The next prime is 51581083. The reversal of 51581081 is 18018515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40960000 + 10621081 = 6400^2 + 3259^2 .

It is a cyclic number.

It is not a de Polignac number, because 51581081 - 2⁶ = 51581017 is a prime.

It is a super-2 number, since 2×51581081² = 5321215834257122, which contains 22 as substring.

Together with 51581083, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51581083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25790540 + 25790541.

It is an arithmetic number, because the mean of its divisors is an integer number (25790541).

Almost surely, 2^51581081 is an apocalyptic number.

It is an amenable number.

51581081 is a deficient number, since it is larger than the sum of its proper divisors (1).

51581081 is an equidigital number, since it uses as much as digits as its factorization.

51581081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 29.

The square root of 51581081 is about 7181.9970064043. The cubic root of 51581081 is about 372.2460915495.

Adding to 51581081 its reverse (18018515), we get a palindrome (69599596).

The spelling of 51581081 in words is "fifty-one million, five hundred eighty-one thousand, eighty-one".