51216505 has 8 divisors (see below), whose sum is σ = 61718400. Its totient is φ = 40800816.

The previous prime is 51216493. The next prime is 51216509. The reversal of 51216505 is 50561215.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51216505 - 2⁹ = 51215993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51216505.

It is not an unprimeable number, because it can be changed into a prime (51216509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20235 + ... + 22624.

It is an arithmetic number, because the mean of its divisors is an integer number (7714800).

Almost surely, 2^51216505 is an apocalyptic number.

It is an amenable number.

51216505 is a deficient number, since it is larger than the sum of its proper divisors (10501895).

51216505 is a wasteful number, since it uses less digits than its factorization.

51216505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43103.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 51216505 is about 7156.5707570037. The cubic root of 51216505 is about 371.3670031438.

The spelling of 51216505 in words is "fifty-one million, two hundred sixteen thousand, five hundred five".