55220640 has 96 divisors (see below), whose sum is σ = 179988480. Its totient is φ = 14214144.

The previous prime is 55220623. The next prime is 55220657. The reversal of 55220640 is 4602255.

It is an interprime number because it is at equal distance from previous prime (55220623) and next prime (55220657).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 55220640.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 11937 + ... + 15903.

It is an arithmetic number, because the mean of its divisors is an integer number (1874880).

Almost surely, 2^55220640 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 55220640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89994240).

55220640 is an abundant number, since it is smaller than the sum of its proper divisors (124767840).

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

55220640 is a wasteful number, since it uses less digits than its factorization.

55220640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4014 (or 4006 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 55220640 is about 7431.0591438906. The cubic root of 55220640 is about 380.8031029806.

Adding to 55220640 its reverse (4602255), we get a palindrome (59822895).

The spelling of 55220640 in words is "fifty-five million, two hundred twenty thousand, six hundred forty".