55640280 has 128 divisors (see below), whose sum is σ = 175633920. Its totient is φ = 14085120.

The previous prime is 55640279. The next prime is 55640281. The reversal of 55640280 is 8204655.

It is an interprime number because it is at equal distance from previous prime (55640279) and next prime (55640281).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55640281) 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, 211429 + ... + 211691.

It is an arithmetic number, because the mean of its divisors is an integer number (1372140).

Almost surely, 2^55640280 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 55640280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87816960).

55640280 is an abundant number, since it is smaller than the sum of its proper divisors (119993640).

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

55640280 is a wasteful number, since it uses less digits than its factorization.

55640280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361 (or 357 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 55640280 is about 7459.2412482772. The cubic root of 55640280 is about 381.7652862201.

The spelling of 55640280 in words is "fifty-five million, six hundred forty thousand, two hundred eighty".