51872218721685 has 24 divisors (see below), whose sum is σ = 89914158813024. Its totient is φ = 27664471617120.

The previous prime is 51872218721681. The next prime is 51872218721723. The reversal of 51872218721685 is 58612781227815.

It is a happy number.

51872218721685 is a `hidden beast` number, since 5 + 187 + 221 + 8 + 72 + 168 + 5 = 666.

It is not a de Polignac number, because 51872218721685 - 2² = 51872218721681 is a prime.

It is a super-2 number, since 2×51872218721685² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51872218721681) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13056111 + ... + 16559180.

It is an arithmetic number, because the mean of its divisors is an integer number (3746423283876).

Almost surely, 2^{51872218721685} is an apocalyptic number.

It is an amenable number.

51872218721685 is a deficient number, since it is larger than the sum of its proper divisors (38041940091339).

51872218721685 is a wasteful number, since it uses less digits than its factorization.

51872218721685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29654225 (or 29654222 counting only the distinct ones).

The product of its digits is 30105600, while the sum is 63.

The spelling of 51872218721685 in words is "fifty-one trillion, eight hundred seventy-two billion, two hundred eighteen million, seven hundred twenty-one thousand, six hundred eighty-five".