51530861 has 4 divisors (see below), whose sum is σ = 51744924. Its totient is φ = 51316800.

The previous prime is 51530849. The next prime is 51530867. The reversal of 51530861 is 16803515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16803515 = 5 ⋅3360703.

It can be written as a sum of positive squares in 2 ways, for example, as 23377225 + 28153636 = 4835^2 + 5306^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51530861 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51530867) 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, 106670 + ... + 107151.

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

Almost surely, 2^51530861 is an apocalyptic number.

It is an amenable number.

51530861 is a deficient number, since it is larger than the sum of its proper divisors (214063).

51530861 is a wasteful number, since it uses less digits than its factorization.

51530861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214062.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 51530861 is about 7178.4999129345. The cubic root of 51530861 is about 372.1252444701.

The spelling of 51530861 in words is "fifty-one million, five hundred thirty thousand, eight hundred sixty-one".