51003661 has 2 divisors, whose sum is σ = 51003662. Its totient is φ = 51003660.

The previous prime is 51003653. The next prime is 51003679. The reversal of 51003661 is 16630015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38365636 + 12638025 = 6194^2 + 3555^2 .

It is a cyclic number.

It is not a de Polignac number, because 51003661 - 2³ = 51003653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51003611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25501830 + 25501831.

It is an arithmetic number, because the mean of its divisors is an integer number (25501831).

Almost surely, 2^51003661 is an apocalyptic number.

It is an amenable number.

51003661 is a deficient number, since it is larger than the sum of its proper divisors (1).

51003661 is an equidigital number, since it uses as much as digits as its factorization.

51003661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 51003661 is about 7141.6847452124. The cubic root of 51003661 is about 370.8518502838.

Adding to 51003661 its reverse (16630015), we get a palindrome (67633676).

The spelling of 51003661 in words is "fifty-one million, three thousand, six hundred sixty-one".