51555520 has 56 divisors (see below), whose sum is σ = 124504704. Its totient is φ = 20330496.

The previous prime is 51555499. The next prime is 51555521. The reversal of 51555520 is 2555515.

It is a happy number.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (51555521) 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, 22257 + ... + 24463.

Almost surely, 2^51555520 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 51555520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62252352).

51555520 is an abundant number, since it is smaller than the sum of its proper divisors (72949184).

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

51555520 is a wasteful number, since it uses less digits than its factorization.

51555520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2297 (or 2287 counting only the distinct ones).

The product of its (nonzero) digits is 6250, while the sum is 28.

The square root of 51555520 is about 7180.2172669077. The cubic root of 51555520 is about 372.1845925508.

The spelling of 51555520 in words is "fifty-one million, five hundred fifty-five thousand, five hundred twenty".