51155420 has 48 divisors (see below), whose sum is σ = 112492800. Its totient is φ = 19514880.

The previous prime is 51155387. The next prime is 51155443. The reversal of 51155420 is 2455115.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51125 + ... + 52115.

It is an arithmetic number, because the mean of its divisors is an integer number (2343600).

Almost surely, 2^51155420 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 51155420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56246400).

51155420 is an abundant number, since it is smaller than the sum of its proper divisors (61337380).

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

51155420 is a wasteful number, since it uses less digits than its factorization.

51155420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118 (or 1116 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 51155420 is about 7152.3017274161. The cubic root of 51155420 is about 371.2193035040.

The spelling of 51155420 in words is "fifty-one million, one hundred fifty-five thousand, four hundred twenty".