51279920 has 40 divisors (see below), whose sum is σ = 119925360. Its totient is φ = 20391680.

The previous prime is 51279913. The next prime is 51279929. The reversal of 51279920 is 2997215.

It is a Cunningham number, because it is equal to 7161²-1.

It is a tau number, because it is divible by the number of its divisors (40).

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (51279929) 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 7 ways as a sum of consecutive naturals, for example, 12530 + ... + 16110.

It is an arithmetic number, because the mean of its divisors is an integer number (2998134).

Almost surely, 2^51279920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51279920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59962680).

51279920 is an abundant number, since it is smaller than the sum of its proper divisors (68645440).

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

51279920 is a wasteful number, since it uses less digits than its factorization.

51279920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3773 (or 3767 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 51279920 is about 7160.9999301773. Note that the first 4 decimals coincide. The cubic root of 51279920 is about 371.5202123837.

The spelling of 51279920 in words is "fifty-one million, two hundred seventy-nine thousand, nine hundred twenty".