51729661 has 4 divisors (see below), whose sum is σ = 51744924. Its totient is φ = 51714400.

The previous prime is 51729617. The next prime is 51729683. The reversal of 51729661 is 16692715.

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

It can be written as a sum of positive squares in 2 ways, for example, as 18020025 + 33709636 = 4245^2 + 5806^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51729661 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 51729661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51729361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10 + ... + 10171.

It is an arithmetic number, because the mean of its divisors is an integer number (12936231).

Almost surely, 2^51729661 is an apocalyptic number.

It is an amenable number.

51729661 is a deficient number, since it is larger than the sum of its proper divisors (15263).

51729661 is a wasteful number, since it uses less digits than its factorization.

51729661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15262.

The product of its digits is 22680, while the sum is 37.

The square root of 51729661 is about 7192.3334878188. Note that the first 3 decimals coincide. The cubic root of 51729661 is about 372.6031688769.

The spelling of 51729661 in words is "fifty-one million, seven hundred twenty-nine thousand, six hundred sixty-one".