51501220 has 12 divisors (see below), whose sum is σ = 108152604. Its totient is φ = 20600480.

The previous prime is 51501179. The next prime is 51501221. The reversal of 51501220 is 2210515.

It can be written as a sum of positive squares in 2 ways, for example, as 36072036 + 15429184 = 6006^2 + 3928^2 .

It is a super-2 number, since 2×51501220² = 5304751322976800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 51501194 and 51501203.

It is not an unprimeable number, because it can be changed into a prime (51501221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1287511 + ... + 1287550.

It is an arithmetic number, because the mean of its divisors is an integer number (9012717).

Almost surely, 2^51501220 is an apocalyptic number.

It is an amenable number.

51501220 is an abundant number, since it is smaller than the sum of its proper divisors (56651384).

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

51501220 is a wasteful number, since it uses less digits than its factorization.

51501220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2575070 (or 2575068 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 51501220 is about 7176.4350481280. The cubic root of 51501220 is about 372.0538808916.

Adding to 51501220 its reverse (2210515), we get a palindrome (53711735).

The spelling of 51501220 in words is "fifty-one million, five hundred one thousand, two hundred twenty".