51223320 has 128 divisors (see below), whose sum is σ = 174873600. Its totient is φ = 13329792.

The previous prime is 51223313. The next prime is 51223321. The reversal of 51223320 is 2332215.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 51223293 and 51223302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51223321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45889 + ... + 46991.

It is an arithmetic number, because the mean of its divisors is an integer number (1366200).

Almost surely, 2^51223320 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51223320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87436800).

51223320 is an abundant number, since it is smaller than the sum of its proper divisors (123650280).

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

51223320 is a wasteful number, since it uses less digits than its factorization.

51223320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166 (or 1156 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 51223320 is about 7157.0468770297. The cubic root of 51223320 is about 371.3834740964.

Adding to 51223320 its reverse (2332215), we get a palindrome (53555535).

It can be divided in two parts, 512 and 23320, that added together give a palindrome (23832).

The spelling of 51223320 in words is "fifty-one million, two hundred twenty-three thousand, three hundred twenty".