51299820 has 144 divisors (see below), whose sum is σ = 182905632. Its totient is φ = 11473920.

The previous prime is 51299803. The next prime is 51299827. The reversal of 51299820 is 2899215.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (51299827) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 24744 + ... + 26736.

It is an arithmetic number, because the mean of its divisors is an integer number (1270178).

Almost surely, 2^51299820 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 51299820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91452816).

51299820 is an abundant number, since it is smaller than the sum of its proper divisors (131605812).

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

51299820 is a wasteful number, since it uses less digits than its factorization.

51299820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032 (or 2027 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 51299820 is about 7162.3892661597. The cubic root of 51299820 is about 371.5682643053.

The spelling of 51299820 in words is "fifty-one million, two hundred ninety-nine thousand, eight hundred twenty".