55785309 has 8 divisors (see below), whose sum is σ = 75784032. Its totient is φ = 36488400.

The previous prime is 55785253. The next prime is 55785377. The reversal of 55785309 is 90358755.

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

It is not a de Polignac number, because 55785309 - 2¹⁶ = 55719773 is a prime.

It is a super-2 number, since 2×55785309² = 6224001400450962, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55785209) 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, 175267 + ... + 175584.

It is an arithmetic number, because the mean of its divisors is an integer number (9473004).

Almost surely, 2^55785309 is an apocalyptic number.

It is an amenable number.

55785309 is a deficient number, since it is larger than the sum of its proper divisors (19998723).

55785309 is a wasteful number, since it uses less digits than its factorization.

55785309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350907.

The product of its (nonzero) digits is 189000, while the sum is 42.

The square root of 55785309 is about 7468.9563527979. The cubic root of 55785309 is about 382.0966948186.

The spelling of 55785309 in words is "fifty-five million, seven hundred eighty-five thousand, three hundred nine".