51685145 has 4 divisors (see below), whose sum is σ = 62022180. Its totient is φ = 41348112.

The previous prime is 51685141. The next prime is 51685159. The reversal of 51685145 is 54158615.

It is a happy number.

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 26091664 + 25593481 = 5108^2 + 5059^2 .

It is a cyclic number.

It is not a de Polignac number, because 51685145 - 2² = 51685141 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51685141) 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, 5168510 + ... + 5168519.

It is an arithmetic number, because the mean of its divisors is an integer number (15505545).

Almost surely, 2^51685145 is an apocalyptic number.

It is an amenable number.

51685145 is a deficient number, since it is larger than the sum of its proper divisors (10337035).

51685145 is a wasteful number, since it uses less digits than its factorization.

51685145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10337034.

The product of its digits is 24000, while the sum is 35.

The square root of 51685145 is about 7189.2381376610. The cubic root of 51685145 is about 372.4962568878.

The spelling of 51685145 in words is "fifty-one million, six hundred eighty-five thousand, one hundred forty-five".