55780209 has 6 divisors (see below), whose sum is σ = 80571426. Its totient is φ = 37186800.

The previous prime is 55780189. The next prime is 55780223. The reversal of 55780209 is 90208755.

55780209 is a `hidden beast` number, since 557 + 80 + 20 + 9 = 666.

55780209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 45360225 + 10419984 = 6735^2 + 3228^2 .

It is not a de Polignac number, because 55780209 - 2²³ = 47391601 is a prime.

It is a super-2 number, since 2×55780209² = 6222863432167362, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (55780279) 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 5 ways as a sum of consecutive naturals, for example, 3098892 + ... + 3098909.

It is an arithmetic number, because the mean of its divisors is an integer number (13428571).

Almost surely, 2^55780209 is an apocalyptic number.

It is an amenable number.

55780209 is a deficient number, since it is larger than the sum of its proper divisors (24791217).

55780209 is a wasteful number, since it uses less digits than its factorization.

55780209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6197807 (or 6197804 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The square root of 55780209 is about 7468.6149318331. The cubic root of 55780209 is about 382.0850504594.

The spelling of 55780209 in words is "fifty-five million, seven hundred eighty thousand, two hundred nine".