55551220 has 24 divisors (see below), whose sum is σ = 118137600. Its totient is φ = 21938592.

The previous prime is 55551191. The next prime is 55551229. The reversal of 55551220 is 2215555.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55551229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16000 + ... + 19159.

It is an arithmetic number, because the mean of its divisors is an integer number (4922400).

Almost surely, 2^55551220 is an apocalyptic number.

It is an amenable number.

55551220 is an abundant number, since it is smaller than the sum of its proper divisors (62586380).

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

55551220 is a wasteful number, since it uses less digits than its factorization.

55551220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35247 (or 35245 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 25.

The square root of 55551220 is about 7453.2690814166. The cubic root of 55551220 is about 381.5614879818.

Adding to 55551220 its reverse (2215555), we get a palindrome (57766775).

The spelling of 55551220 in words is "fifty-five million, five hundred fifty-one thousand, two hundred twenty".