51578404391 has 4 divisors (see below), whose sum is σ = 51580004232. Its totient is φ = 51576804552.

The previous prime is 51578404327. The next prime is 51578404417. The reversal of 51578404391 is 19340487515.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19340487515 = 5 ⋅3868097503.

It is a cyclic number.

It is not a de Polignac number, because 51578404391 - 2⁶ = 51578404327 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 (51578403391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 750545 + ... + 816378.

It is an arithmetic number, because the mean of its divisors is an integer number (12895001058).

Almost surely, 2^51578404391 is an apocalyptic number.

51578404391 is a deficient number, since it is larger than the sum of its proper divisors (1599841).

51578404391 is a wasteful number, since it uses less digits than its factorization.

51578404391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1599840.

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 51578404391 in words is "fifty-one billion, five hundred seventy-eight million, four hundred four thousand, three hundred ninety-one".