51720606 has 96 divisors (see below), whose sum is σ = 138797568. Its totient is φ = 14113440.

The previous prime is 51720593. The next prime is 51720607. The reversal of 51720606 is 60602715.

51720606 is a `hidden beast` number, since 51 + 7 + 2 + 0 + 606 = 666.

51720606 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 (27).

It is a self number, because there is not a number n which added to its sum of digits gives 51720606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51720607) 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, 77916 + ... + 78576.

It is an arithmetic number, because the mean of its divisors is an integer number (1445808).

Almost surely, 2^51720606 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51720606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69398784).

51720606 is an abundant number, since it is smaller than the sum of its proper divisors (87076962).

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

51720606 is a wasteful number, since it uses less digits than its factorization.

51720606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708 (or 696 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 51720606 is about 7191.7039705483. The cubic root of 51720606 is about 372.5814268788.

It can be divided in two parts, 51720 and 606, that added together give a triangular number (52326 = T₃₂₃).

The spelling of 51720606 in words is "fifty-one million, seven hundred twenty thousand, six hundred six".