51506215 has 4 divisors (see below), whose sum is σ = 61807464. Its totient is φ = 41204968.

The previous prime is 51506197. The next prime is 51506227. The reversal of 51506215 is 51260515.

51506215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51506215 - 2⁹ = 51505703 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51506215.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 5150617 + ... + 5150626.

It is an arithmetic number, because the mean of its divisors is an integer number (15451866).

Almost surely, 2^51506215 is an apocalyptic number.

51506215 is a deficient number, since it is larger than the sum of its proper divisors (10301249).

51506215 is a wasteful number, since it uses less digits than its factorization.

51506215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10301248.

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

The square root of 51506215 is about 7176.7830537087. The cubic root of 51506215 is about 372.0659087559.

The spelling of 51506215 in words is "fifty-one million, five hundred six thousand, two hundred fifteen".