51215663 has 2 divisors, whose sum is σ = 51215664. Its totient is φ = 51215662.

The previous prime is 51215651. The next prime is 51215677. The reversal of 51215663 is 36651215.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51215663 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51215693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25607831 + 25607832.

It is an arithmetic number, because the mean of its divisors is an integer number (25607832).

Almost surely, 2^51215663 is an apocalyptic number.

51215663 is a deficient number, since it is larger than the sum of its proper divisors (1).

51215663 is an equidigital number, since it uses as much as digits as its factorization.

51215663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5400, while the sum is 29.

The square root of 51215663 is about 7156.5119297043. The cubic root of 51215663 is about 371.3649680399.

Adding to 51215663 its reverse (36651215), we get a palindrome (87866878).

The spelling of 51215663 in words is "fifty-one million, two hundred fifteen thousand, six hundred sixty-three".