55561209 has 8 divisors (see below), whose sum is σ = 80816352. Its totient is φ = 33673440.

The previous prime is 55561193. The next prime is 55561213. The reversal of 55561209 is 90216555.

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

It is not a de Polignac number, because 55561209 - 2⁴ = 55561193 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 1683673 = 55561209 / (5 + 5 + 5 + 6 + 1 + 2 + 0 + 9).

It is a self number, because there is not a number n which added to its sum of digits gives 55561209.

It is not an unprimeable number, because it can be changed into a prime (55561409) 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, 841804 + ... + 841869.

It is an arithmetic number, because the mean of its divisors is an integer number (10102044).

Almost surely, 2^55561209 is an apocalyptic number.

It is an amenable number.

55561209 is a deficient number, since it is larger than the sum of its proper divisors (25255143).

55561209 is a wasteful number, since it uses less digits than its factorization.

55561209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1683687.

The product of its (nonzero) digits is 13500, while the sum is 33.

The square root of 55561209 is about 7453.9391599342. The cubic root of 55561209 is about 381.5843569022.

The spelling of 55561209 in words is "fifty-five million, five hundred sixty-one thousand, two hundred nine".