51221541220 has 24 divisors (see below), whose sum is σ = 107665903800. Its totient is φ = 20469441792.

The previous prime is 51221541143. The next prime is 51221541299. The reversal of 51221541220 is 2214512215.

51221541220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 2889277504 + 48332263716 = 53752^2 + 219846^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1176505 + ... + 1219264.

It is an arithmetic number, because the mean of its divisors is an integer number (4486079325).

Almost surely, 2^51221541220 is an apocalyptic number.

It is an amenable number.

51221541220 is an abundant number, since it is smaller than the sum of its proper divisors (56444362580).

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

51221541220 is a wasteful number, since it uses less digits than its factorization.

51221541220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2396847 (or 2396845 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The spelling of 51221541220 in words is "fifty-one billion, two hundred twenty-one million, five hundred forty-one thousand, two hundred twenty".