51021306 has 96 divisors (see below), whose sum is σ = 134478720. Its totient is φ = 14043456.

The previous prime is 51021241. The next prime is 51021307. The reversal of 51021306 is 60312015.

51021306 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51021307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 698886 + ... + 698958.

It is an arithmetic number, because the mean of its divisors is an integer number (1400820).

Almost surely, 2^51021306 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51021306, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67239360).

51021306 is an abundant number, since it is smaller than the sum of its proper divisors (83457414).

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

51021306 is a wasteful number, since it uses less digits than its factorization.

51021306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 51021306 is about 7142.9199911521. The cubic root of 51021306 is about 370.8946114393.

The spelling of 51021306 in words is "fifty-one million, twenty-one thousand, three hundred six".