51397819 has 4 divisors (see below), whose sum is σ = 56070360. Its totient is φ = 46725280.

The previous prime is 51397813. The next prime is 51397867. The reversal of 51397819 is 91879315.

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 51397819 - 2³ = 51397811 is a prime.

It is a super-4 number, since 4×51397819⁴ (a number of 32 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51397811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2336254 + ... + 2336275.

It is an arithmetic number, because the mean of its divisors is an integer number (14017590).

Almost surely, 2^51397819 is an apocalyptic number.

51397819 is a deficient number, since it is larger than the sum of its proper divisors (4672541).

51397819 is a wasteful number, since it uses less digits than its factorization.

51397819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4672540.

The product of its digits is 68040, while the sum is 43.

The square root of 51397819 is about 7169.2272247433. The cubic root of 51397819 is about 371.8047183896.

The spelling of 51397819 in words is "fifty-one million, three hundred ninety-seven thousand, eight hundred nineteen".