51221566 has 16 divisors (see below), whose sum is σ = 84291840. Its totient is φ = 23150680.

The previous prime is 51221563. The next prime is 51221593. The reversal of 51221566 is 66512215.

51221566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51221563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2566 + ... + 10441.

It is an arithmetic number, because the mean of its divisors is an integer number (5268240).

Almost surely, 2^51221566 is an apocalyptic number.

51221566 is a deficient number, since it is larger than the sum of its proper divisors (33070274).

51221566 is a wasteful number, since it uses less digits than its factorization.

51221566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13199.

The product of its digits is 3600, while the sum is 28.

The square root of 51221566 is about 7156.9243394073. The cubic root of 51221566 is about 371.3792350503.

The spelling of 51221566 in words is "fifty-one million, two hundred twenty-one thousand, five hundred sixty-six".