55491840 has 108 divisors (see below), whose sum is σ = 192035844. Its totient is φ = 14794752.

The previous prime is 55491827. The next prime is 55491841. The reversal of 55491840 is 4819455.

It can be written as a sum of positive squares in 2 ways, for example, as 11614464 + 43877376 = 3408^2 + 6624^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 55491795 and 55491804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55491841) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9112 + ... + 13928.

Almost surely, 2^55491840 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 55491840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96017922).

55491840 is an abundant number, since it is smaller than the sum of its proper divisors (136544004).

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

55491840 is a wasteful number, since it uses less digits than its factorization.

55491840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4844 (or 4827 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 55491840 is about 7449.2845294028. The cubic root of 55491840 is about 381.4254861751.

The spelling of 55491840 in words is "fifty-five million, four hundred ninety-one thousand, eight hundred forty".