55209331 has 4 divisors (see below), whose sum is σ = 56114464. Its totient is φ = 54304200.

The previous prime is 55209311. The next prime is 55209337. The reversal of 55209331 is 13390255.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55209331 is a prime.

It is a super-2 number, since 2×55209331² = 6096140458935122, which contains 22 as substring.

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 55209331.

It is not an unprimeable number, because it can be changed into a prime (55209337) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 452475 + ... + 452596.

It is an arithmetic number, because the mean of its divisors is an integer number (14028616).

Almost surely, 2^55209331 is an apocalyptic number.

55209331 is a deficient number, since it is larger than the sum of its proper divisors (905133).

55209331 is an equidigital number, since it uses as much as digits as its factorization.

55209331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905132.

The product of its (nonzero) digits is 4050, while the sum is 28.

The square root of 55209331 is about 7430.2981770586. The cubic root of 55209331 is about 380.7771054773. Note that the first 3 decimals are identical.

Adding to 55209331 its reverse (13390255), we get a palindrome (68599586).

The spelling of 55209331 in words is "fifty-five million, two hundred nine thousand, three hundred thirty-one".