51721725447 has 16 divisors (see below), whose sum is σ = 87571175680. Its totient is φ = 29555271576.

The previous prime is 51721725397. The next prime is 51721725457. The reversal of 51721725447 is 74452712715.

It is a happy number.

51721725447 is a `hidden beast` number, since 5 + 17 + 21 + 72 + 544 + 7 = 666.

It is not a de Polignac number, because 51721725447 - 2¹¹ = 51721723399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51721725457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 136829773 + ... + 136830150.

It is an arithmetic number, because the mean of its divisors is an integer number (5473198480).

Almost surely, 2^51721725447 is an apocalyptic number.

51721725447 is a deficient number, since it is larger than the sum of its proper divisors (35849450233).

51721725447 is a wasteful number, since it uses less digits than its factorization.

51721725447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273659939 (or 273659933 counting only the distinct ones).

The product of its digits is 548800, while the sum is 45.

The spelling of 51721725447 in words is "fifty-one billion, seven hundred twenty-one million, seven hundred twenty-five thousand, four hundred forty-seven".