51223220 has 24 divisors (see below), whose sum is σ = 108297000. Its totient is φ = 20350592.

The previous prime is 51223217. The next prime is 51223247. The reversal of 51223220 is 2232215.

51223220 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 6574096 + 44649124 = 2564^2 + 6682^2 .

It is a congruent number.

It is an unprimeable number.

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, 5615 + ... + 11574.

It is an arithmetic number, because the mean of its divisors is an integer number (4512375).

Almost surely, 2^51223220 is an apocalyptic number.

It is an amenable number.

51223220 is an abundant number, since it is smaller than the sum of its proper divisors (57073780).

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

51223220 is a wasteful number, since it uses less digits than its factorization.

51223220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17347 (or 17345 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 51223220 is about 7157.0398909046. The cubic root of 51223220 is about 371.3832324202.

Adding to 51223220 its reverse (2232215), we get a palindrome (53455435).

It can be divided in two parts, 512 and 23220, that added together give a palindrome (23732).

The spelling of 51223220 in words is "fifty-one million, two hundred twenty-three thousand, two hundred twenty".