51505665 has 64 divisors (see below), whose sum is σ = 92192256. Its totient is φ = 24440832.

The previous prime is 51505621. The next prime is 51505669. The reversal of 51505665 is 56650515.

It is not a de Polignac number, because 51505665 - 2¹⁰ = 51504641 is a prime.

51505665 is a modest number, since divided by 5665 gives 5150 as remainder.

It is not an unprimeable number, because it can be changed into a prime (51505669) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 500004 + ... + 500106.

It is an arithmetic number, because the mean of its divisors is an integer number (1440504).

Almost surely, 2^51505665 is an apocalyptic number.

It is an amenable number.

51505665 is a deficient number, since it is larger than the sum of its proper divisors (40686591).

51505665 is a wasteful number, since it uses less digits than its factorization.

51505665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218.

The product of its (nonzero) digits is 22500, while the sum is 33.

The square root of 51505665 is about 7176.7447356026. The cubic root of 51505665 is about 372.0645844046.

The spelling of 51505665 in words is "fifty-one million, five hundred five thousand, six hundred sixty-five".