55661309 has 4 divisors (see below), whose sum is σ = 60721440. Its totient is φ = 50601180.

The previous prime is 55661273. The next prime is 55661339. The reversal of 55661309 is 90316655.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 55661309 - 2²⁴ = 38884093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55661339) 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, 2530049 + ... + 2530070.

It is an arithmetic number, because the mean of its divisors is an integer number (15180360).

Almost surely, 2^55661309 is an apocalyptic number.

It is an amenable number.

55661309 is a deficient number, since it is larger than the sum of its proper divisors (5060131).

55661309 is a wasteful number, since it uses less digits than its factorization.

55661309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5060130.

The product of its (nonzero) digits is 24300, while the sum is 35.

The square root of 55661309 is about 7460.6507088859. The cubic root of 55661309 is about 381.8133756679.

The spelling of 55661309 in words is "fifty-five million, six hundred sixty-one thousand, three hundred nine".