51720630 has 128 divisors (see below), whose sum is σ = 146966400. Its totient is φ = 11526144.

The previous prime is 51720607. The next prime is 51720637. The reversal of 51720630 is 3602715.

51720630 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 51720630.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51720637) 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 63 ways as a sum of consecutive naturals, for example, 192136 + ... + 192404.

It is an arithmetic number, because the mean of its divisors is an integer number (1148175).

Almost surely, 2^51720630 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51720630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73483200).

51720630 is an abundant number, since it is smaller than the sum of its proper divisors (95245770).

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

51720630 is a wasteful number, since it uses less digits than its factorization.

51720630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338.

The product of its (nonzero) digits is 1260, while the sum is 24.

The square root of 51720630 is about 7191.7056391374. The cubic root of 51720630 is about 372.5814845087.

The spelling of 51720630 in words is "fifty-one million, seven hundred twenty thousand, six hundred thirty".