55143991 has 8 divisors (see below), whose sum is σ = 63152000. Its totient is φ = 47168568.

The previous prime is 55143989. The next prime is 55144013. The reversal of 55143991 is 19934155.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55143991 - 2¹ = 55143989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55143991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55143961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4401 + ... + 11386.

It is an arithmetic number, because the mean of its divisors is an integer number (7894000).

Almost surely, 2^55143991 is an apocalyptic number.

55143991 is a deficient number, since it is larger than the sum of its proper divisors (8008009).

55143991 is a wasteful number, since it uses less digits than its factorization.

55143991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16293.

The product of its digits is 24300, while the sum is 37.

The square root of 55143991 is about 7425.9000127931. The cubic root of 55143991 is about 380.6268301694.

The spelling of 55143991 in words is "fifty-five million, one hundred forty-three thousand, nine hundred ninety-one".