51501521 has 4 divisors (see below), whose sum is σ = 52893492. Its totient is φ = 50109552.

The previous prime is 51501503. The next prime is 51501539. The reversal of 51501521 is 12510515.

It is a happy number.

51501521 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 an interprime number because it is at equal distance from previous prime (51501503) and next prime (51501539).

It can be written as a sum of positive squares in 2 ways, for example, as 25897921 + 25603600 = 5089^2 + 5060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51501521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51501493 and 51501502.

It is not an unprimeable number, because it can be changed into a prime (51501221) 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 in 3 ways as a sum of consecutive naturals, for example, 695930 + ... + 696003.

It is an arithmetic number, because the mean of its divisors is an integer number (13223373).

Almost surely, 2^51501521 is an apocalyptic number.

It is an amenable number.

51501521 is a deficient number, since it is larger than the sum of its proper divisors (1391971).

51501521 is a wasteful number, since it uses less digits than its factorization.

51501521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1391970.

The product of its (nonzero) digits is 250, while the sum is 20.

The square root of 51501521 is about 7176.4560195127. The cubic root of 51501521 is about 372.0546057159.

The spelling of 51501521 in words is "fifty-one million, five hundred one thousand, five hundred twenty-one".