51578491 has 4 divisors (see below), whose sum is σ = 51657184. Its totient is φ = 51499800.

The previous prime is 51578477. The next prime is 51578503. The reversal of 51578491 is 19487515.

It is a happy number.

51578491 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.

It is a cyclic number.

It is not a de Polignac number, because 51578491 - 2⁷ = 51578363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51578431) 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, 38355 + ... + 39676.

It is an arithmetic number, because the mean of its divisors is an integer number (12914296).

Almost surely, 2^51578491 is an apocalyptic number.

51578491 is a deficient number, since it is larger than the sum of its proper divisors (78693).

51578491 is an equidigital number, since it uses as much as digits as its factorization.

51578491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78692.

The product of its digits is 50400, while the sum is 40.

The square root of 51578491 is about 7181.8166921748. The cubic root of 51578491 is about 372.2398610124.

The spelling of 51578491 in words is "fifty-one million, five hundred seventy-eight thousand, four hundred ninety-one".