55211520 has 320 divisors, whose sum is σ = 219985920. Its totient is φ = 11501568.

The previous prime is 55211509. The next prime is 55211521. The reversal of 55211520 is 2511255.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55211521) 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, 698841 + ... + 698919.

It is an arithmetic number, because the mean of its divisors is an integer number (687456).

Almost surely, 2^55211520 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 55211520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109992960).

55211520 is an abundant number, since it is smaller than the sum of its proper divisors (164774400).

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

55211520 is a wasteful number, since it uses less digits than its factorization.

55211520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 55211520 is about 7430.4454778970. The cubic root of 55211520 is about 380.7821379000.

Adding to 55211520 its reverse (2511255), we get a palindrome (57722775).

It can be divided in two parts, 55 and 211520, that added together give a triangular number (211575 = T₆₅₀).

The spelling of 55211520 in words is "fifty-five million, two hundred eleven thousand, five hundred twenty".