51221606605821 has 48 divisors (see below), whose sum is σ = 75590639467200. Its totient is φ = 33411063119616.

The previous prime is 51221606605787. The next prime is 51221606605879. The reversal of 51221606605821 is 12850660612215.

51221606605821 is a `hidden beast` number, since 5 + 1 + 2 + 2 + 1 + 6 + 0 + 6 + 60 + 582 + 1 = 666.

It is not a de Polignac number, because 51221606605821 - 2¹¹ = 51221606603773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51221606605121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2856904785 + ... + 2856922713.

It is an arithmetic number, because the mean of its divisors is an integer number (1574804988900).

Almost surely, 2^{51221606605821} is an apocalyptic number.

It is an amenable number.

51221606605821 is a deficient number, since it is larger than the sum of its proper divisors (24369032861379).

51221606605821 is a wasteful number, since it uses less digits than its factorization.

51221606605821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34170 (or 34167 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 51221606605821 in words is "fifty-one trillion, two hundred twenty-one billion, six hundred six million, six hundred five thousand, eight hundred twenty-one".