51399939 has 8 divisors (see below), whose sum is σ = 68841472. Its totient is φ = 34112520.

The previous prime is 51399923. The next prime is 51399941. The reversal of 51399939 is 93999315.

It is a happy number.

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

It is not a de Polignac number, because 51399939 - 2⁴ = 51399923 is a prime.

It is a super-3 number, since 3×51399939³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51399979) 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, 37747 + ... + 39084.

It is an arithmetic number, because the mean of its divisors is an integer number (8605184).

Almost surely, 2^51399939 is an apocalyptic number.

51399939 is a deficient number, since it is larger than the sum of its proper divisors (17441533).

51399939 is a wasteful number, since it uses less digits than its factorization.

51399939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77057.

The product of its digits is 295245, while the sum is 48.

The square root of 51399939 is about 7169.3750773690. The cubic root of 51399939 is about 371.8098302483.

The spelling of 51399939 in words is "fifty-one million, three hundred ninety-nine thousand, nine hundred thirty-nine".