51439920 has 160 divisors (see below), whose sum is σ = 185369088. Its totient is φ = 11556864.

The previous prime is 51439919. The next prime is 51439931. The reversal of 51439920 is 2993415.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 112332 + ... + 112788.

Almost surely, 2^51439920 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 51439920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92684544).

51439920 is an abundant number, since it is smaller than the sum of its proper divisors (133929168).

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

51439920 is a wasteful number, since it uses less digits than its factorization.

51439920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547 (or 541 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 51439920 is about 7172.1628537004. The cubic root of 51439920 is about 371.9062082888.

The spelling of 51439920 in words is "fifty-one million, four hundred thirty-nine thousand, nine hundred twenty".