51720504 has 64 divisors (see below), whose sum is σ = 141696000. Its totient is φ = 15601920.

The previous prime is 51720499. The next prime is 51720509. The reversal of 51720504 is 40502715.

It is an interprime number because it is at equal distance from previous prime (51720499) and next prime (51720509).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51720509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107737 + ... + 108215.

It is an arithmetic number, because the mean of its divisors is an integer number (2214000).

Almost surely, 2^51720504 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 51720504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (70848000).

51720504 is an abundant number, since it is smaller than the sum of its proper divisors (89975496).

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

51720504 is a wasteful number, since it uses less digits than its factorization.

51720504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908 (or 904 counting only the distinct ones).

The product of its (nonzero) digits is 1400, while the sum is 24.

The square root of 51720504 is about 7191.6968790404. The cubic root of 51720504 is about 372.5811819517.

The spelling of 51720504 in words is "fifty-one million, seven hundred twenty thousand, five hundred four".