55015220 has 24 divisors (see below), whose sum is σ = 124419624. Its totient is φ = 20313216.

The previous prime is 55015217. The next prime is 55015223. The reversal of 55015220 is 2251055.

It is an interprime number because it is at equal distance from previous prime (55015217) and next prime (55015223).

It can be written as a sum of positive squares in 4 ways, for example, as 1227664 + 53787556 = 1108^2 + 7334^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 55015192 and 55015201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55015223) 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, 105539 + ... + 106058.

It is an arithmetic number, because the mean of its divisors is an integer number (5184151).

Almost surely, 2^55015220 is an apocalyptic number.

It is an amenable number.

55015220 is an abundant number, since it is smaller than the sum of its proper divisors (69404404).

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

55015220 is a wasteful number, since it uses less digits than its factorization.

55015220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211619 (or 211617 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 55015220 is about 7417.2245483065. The cubic root of 55015220 is about 380.3303221963.

Adding to 55015220 its reverse (2251055), we get a palindrome (57266275).

The spelling of 55015220 in words is "fifty-five million, fifteen thousand, two hundred twenty".