55381531 has 4 divisors (see below), whose sum is σ = 57168064. Its totient is φ = 53595000.

The previous prime is 55381519. The next prime is 55381553. The reversal of 55381531 is 13518355.

55381531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13518355 = 5 ⋅2703671.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55381531 is a prime.

It is a super-2 number, since 2×55381531² = 6134227951807922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 1786501 = 55381531 / (5 + 5 + 3 + 8 + 1 + 5 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55381493 and 55381502.

It is not an unprimeable number, because it can be changed into a prime (55381591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 893220 + ... + 893281.

It is an arithmetic number, because the mean of its divisors is an integer number (14292016).

Almost surely, 2^55381531 is an apocalyptic number.

55381531 is a deficient number, since it is larger than the sum of its proper divisors (1786533).

55381531 is a wasteful number, since it uses less digits than its factorization.

55381531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1786532.

The product of its digits is 9000, while the sum is 31.

The square root of 55381531 is about 7441.8768466026. The cubic root of 55381531 is about 381.1725806786.

Adding to 55381531 its reverse (13518355), we get a palindrome (68899886).

The spelling of 55381531 in words is "fifty-five million, three hundred eighty-one thousand, five hundred thirty-one".