51397721186 has 64 divisors (see below), whose sum is σ = 92712812544. Its totient is φ = 20907633600.

The previous prime is 51397721159. The next prime is 51397721197. The reversal of 51397721186 is 68112779315.

It is a happy number.

It is a super-2 number, since 2×51397721186² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6066125 + ... + 6074591.

It is an arithmetic number, because the mean of its divisors is an integer number (1448637696).

Almost surely, 2^51397721186 is an apocalyptic number.

51397721186 is a deficient number, since it is larger than the sum of its proper divisors (41315091358).

51397721186 is a wasteful number, since it uses less digits than its factorization.

51397721186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8775.

The product of its digits is 635040, while the sum is 50.

The spelling of 51397721186 in words is "fifty-one billion, three hundred ninety-seven million, seven hundred twenty-one thousand, one hundred eighty-six".