51278509 has 8 divisors (see below), whose sum is σ = 51958368. Its totient is φ = 50603280.

The previous prime is 51278453. The next prime is 51278527. The reversal of 51278509 is 90587215.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51278509 - 2⁹ = 51277997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51278009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24814 + ... + 26800.

It is an arithmetic number, because the mean of its divisors is an integer number (6494796).

Almost surely, 2^51278509 is an apocalyptic number.

It is an amenable number.

51278509 is a deficient number, since it is larger than the sum of its proper divisors (679859).

51278509 is a wasteful number, since it uses less digits than its factorization.

51278509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2315.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 51278509 is about 7160.9014097389. The cubic root of 51278509 is about 371.5168048132.

The spelling of 51278509 in words is "fifty-one million, two hundred seventy-eight thousand, five hundred nine".