51785520 has 80 divisors (see below), whose sum is σ = 161894400. Its totient is φ = 13692672.

The previous prime is 51785497. The next prime is 51785521. The reversal of 51785520 is 2558715.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (51785521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29631 + ... + 31329.

It is an arithmetic number, because the mean of its divisors is an integer number (2023680).

Almost surely, 2^51785520 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 51785520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80947200).

51785520 is an abundant number, since it is smaller than the sum of its proper divisors (110108880).

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

51785520 is a wasteful number, since it uses less digits than its factorization.

51785520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1842 (or 1836 counting only the distinct ones).

The product of its (nonzero) digits is 14000, while the sum is 33.

The square root of 51785520 is about 7196.2156721432. The cubic root of 51785520 is about 372.7372360829.

The spelling of 51785520 in words is "fifty-one million, seven hundred eighty-five thousand, five hundred twenty".