51555609 has 28 divisors (see below), whose sum is σ = 88349376. Its totient is φ = 29457432.

The previous prime is 51555601. The next prime is 51555613. The reversal of 51555609 is 90655515.

It is not a de Polignac number, because 51555609 - 2³ = 51555601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51555601) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 52 + ... + 10154.

Almost surely, 2^51555609 is an apocalyptic number.

It is an amenable number.

51555609 is a deficient number, since it is larger than the sum of its proper divisors (36793767).

51555609 is an equidigital number, since it uses as much as digits as its factorization.

51555609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10128 (or 10113 counting only the distinct ones).

The product of its (nonzero) digits is 33750, while the sum is 36.

The square root of 51555609 is about 7180.2234644891. The cubic root of 51555609 is about 372.1848067174.

The spelling of 51555609 in words is "fifty-one million, five hundred fifty-five thousand, six hundred nine".