51490381 has 2 divisors, whose sum is σ = 51490382. Its totient is φ = 51490380.

The previous prime is 51490363. The next prime is 51490409. The reversal of 51490381 is 18309415.

51490381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29484900 + 22005481 = 5430^2 + 4691^2 .

It is a cyclic number.

It is not a de Polignac number, because 51490381 - 2⁷ = 51490253 is a prime.

It is a super-2 number, since 2×51490381² = 5302518671050322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51490321) 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 as a sum of consecutive naturals, namely, 25745190 + 25745191.

It is an arithmetic number, because the mean of its divisors is an integer number (25745191).

Almost surely, 2^51490381 is an apocalyptic number.

It is an amenable number.

51490381 is a deficient number, since it is larger than the sum of its proper divisors (1).

51490381 is an equidigital number, since it uses as much as digits as its factorization.

51490381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 51490381 is about 7175.6798284204. The cubic root of 51490381 is about 372.0277781122.

Adding to 51490381 its reverse (18309415), we get a palindrome (69799796).

The spelling of 51490381 in words is "fifty-one million, four hundred ninety thousand, three hundred eighty-one".