51531745 has 4 divisors (see below), whose sum is σ = 61838100. Its totient is φ = 41225392.

The previous prime is 51531737. The next prime is 51531749. The reversal of 51531745 is 54713515.

51531745 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, and also an emirpimes, since its reverse is a distinct semiprime: 54713515 = 5 ⋅10942703.

It can be written as a sum of positive squares in 2 ways, for example, as 21752896 + 29778849 = 4664^2 + 5457^2 .

It is a cyclic number.

It is not a de Polignac number, because 51531745 - 2³ = 51531737 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (51531749) 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, 5153170 + ... + 5153179.

It is an arithmetic number, because the mean of its divisors is an integer number (15459525).

Almost surely, 2^51531745 is an apocalyptic number.

It is an amenable number.

51531745 is a deficient number, since it is larger than the sum of its proper divisors (10306355).

51531745 is a wasteful number, since it uses less digits than its factorization.

51531745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10306354.

The product of its digits is 10500, while the sum is 31.

The square root of 51531745 is about 7178.5614854231. The cubic root of 51531745 is about 372.1273723655.

The spelling of 51531745 in words is "fifty-one million, five hundred thirty-one thousand, seven hundred forty-five".