51720605 has 8 divisors (see below), whose sum is σ = 62103552. Its totient is φ = 41350608.

The previous prime is 51720593. The next prime is 51720607. The reversal of 51720605 is 50602715.

51720605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51720605 - 2¹⁰ = 51719581 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 7 ways as a sum of consecutive naturals, for example, 12644 + ... + 16226.

It is an arithmetic number, because the mean of its divisors is an integer number (7762944).

Almost surely, 2^51720605 is an apocalyptic number.

It is an amenable number.

51720605 is a deficient number, since it is larger than the sum of its proper divisors (10382947).

51720605 is a wasteful number, since it uses less digits than its factorization.

51720605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6475.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 51720605 is about 7191.7039010237. The cubic root of 51720605 is about 372.5814244776.

It can be divided in two parts, 51720 and 605, that added together give a palindrome (52325).

The spelling of 51720605 in words is "fifty-one million, seven hundred twenty thousand, six hundred five".