55399860 has 72 divisors (see below), whose sum is σ = 173857320. Its totient is φ = 14262528.

The previous prime is 55399853. The next prime is 55399891. The reversal of 55399860 is 6899355.

55399860 is a `hidden beast` number, since 553 + 9 + 98 + 6 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 23386896 + 32012964 = 4836^2 + 5658^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 87 + ... + 10526.

It is an arithmetic number, because the mean of its divisors is an integer number (2414685).

Almost surely, 2^55399860 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 55399860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86928660).

55399860 is an abundant number, since it is smaller than the sum of its proper divisors (118457460).

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

55399860 is a wasteful number, since it uses less digits than its factorization.

55399860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10657 (or 10652 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The square root of 55399860 is about 7443.1082217042. The cubic root of 55399860 is about 381.2146268355.

The spelling of 55399860 in words is "fifty-five million, three hundred ninety-nine thousand, eight hundred sixty".