51665665 has 8 divisors (see below), whose sum is σ = 62346240. Its totient is φ = 41100912.

The previous prime is 51665609. The next prime is 51665687. The reversal of 51665665 is 56656615.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51665665 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27969 + ... + 29758.

It is an arithmetic number, because the mean of its divisors is an integer number (7793280).

Almost surely, 2^51665665 is an apocalyptic number.

It is an amenable number.

51665665 is a deficient number, since it is larger than the sum of its proper divisors (10680575).

51665665 is a wasteful number, since it uses less digits than its factorization.

51665665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57911.

The product of its digits is 162000, while the sum is 40.

The square root of 51665665 is about 7187.8832071758. The cubic root of 51665665 is about 372.4494533759.

The spelling of 51665665 in words is "fifty-one million, six hundred sixty-five thousand, six hundred sixty-five".