55381440 has 56 divisors (see below), whose sum is σ = 175839120. Its totient is φ = 14768128.

The previous prime is 55381439. The next prime is 55381457. The reversal of 55381440 is 4418355.

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

It is a junction number, because it is equal to n+sod(n) for n = 55381398 and 55381407.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 27885 + ... + 29804.

Almost surely, 2^55381440 is an apocalyptic number.

It is an amenable number.

55381440 is an abundant number, since it is smaller than the sum of its proper divisors (120457680).

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

55381440 is a wasteful number, since it uses less digits than its factorization.

55381440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57709 (or 57699 counting only the distinct ones).

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

The square root of 55381440 is about 7441.8707325511. The cubic root of 55381440 is about 381.1723719043.

Adding to 55381440 its reverse (4418355), we get a palindrome (59799795).

The spelling of 55381440 in words is "fifty-five million, three hundred eighty-one thousand, four hundred forty".