51721725245 has 4 divisors (see below), whose sum is σ = 62066070300. Its totient is φ = 41377380192.

The previous prime is 51721725241. The next prime is 51721725247. The reversal of 51721725245 is 54252712715.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54252712715 = 5 ⋅10850542543.

It can be written as a sum of positive squares in 2 ways, for example, as 38448150724 + 13273574521 = 196082^2 + 115211^2 .

It is a cyclic number.

It is not a de Polignac number, because 51721725245 - 2² = 51721725241 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51721725241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5172172520 + ... + 5172172529.

It is an arithmetic number, because the mean of its divisors is an integer number (15516517575).

Almost surely, 2^51721725245 is an apocalyptic number.

It is an amenable number.

51721725245 is a deficient number, since it is larger than the sum of its proper divisors (10344345055).

51721725245 is a wasteful number, since it uses less digits than its factorization.

51721725245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10344345054.

The product of its digits is 196000, while the sum is 41.

The spelling of 51721725245 in words is "fifty-one billion, seven hundred twenty-one million, seven hundred twenty-five thousand, two hundred forty-five".