51139872 has 72 divisors (see below), whose sum is σ = 166211136. Its totient is φ = 14610816.

The previous prime is 51139871. The next prime is 51139889. The reversal of 51139872 is 27893115.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (51139871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10668 + ... + 14699.

It is an arithmetic number, because the mean of its divisors is an integer number (2308488).

Almost surely, 2^51139872 is an apocalyptic number.

It is an amenable number.

51139872 is an abundant number, since it is smaller than the sum of its proper divisors (115071264).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51139872 is a wasteful number, since it uses less digits than its factorization.

51139872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25390 (or 25379 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 51139872 is about 7151.2147219895. The cubic root of 51139872 is about 371.1816906595.

The spelling of 51139872 in words is "fifty-one million, one hundred thirty-nine thousand, eight hundred seventy-two".