51605665 has 8 divisors (see below), whose sum is σ = 62673408. Its totient is φ = 40786800.

The previous prime is 51605663. The next prime is 51605677. The reversal of 51605665 is 56650615.

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

It is not a de Polignac number, because 51605665 - 2¹ = 51605663 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51605665.

It is not an unprimeable number, because it can be changed into a prime (51605663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61761 + ... + 62590.

It is an arithmetic number, because the mean of its divisors is an integer number (7834176).

Almost surely, 2^51605665 is an apocalyptic number.

It is an amenable number.

51605665 is a deficient number, since it is larger than the sum of its proper divisors (11067743).

51605665 is a wasteful number, since it uses less digits than its factorization.

51605665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124439.

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 51605665 is about 7183.7083042117. The cubic root of 51605665 is about 372.3052207513.

The spelling of 51605665 in words is "fifty-one million, six hundred five thousand, six hundred sixty-five".