51665105 has 4 divisors (see below), whose sum is σ = 61998132. Its totient is φ = 41332080.

The previous prime is 51665101. The next prime is 51665111. The reversal of 51665105 is 50156615.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50156615 = 5 ⋅10031323.

It can be written as a sum of positive squares in 2 ways, for example, as 39337984 + 12327121 = 6272^2 + 3511^2 .

It is not a de Polignac number, because 51665105 - 2² = 51665101 is a prime.

It is a super-2 number, since 2×51665105² = 5338566149322050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51665101) 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 3 ways as a sum of consecutive naturals, for example, 5166506 + ... + 5166515.

It is an arithmetic number, because the mean of its divisors is an integer number (15499533).

Almost surely, 2^51665105 is an apocalyptic number.

It is an amenable number.

51665105 is a deficient number, since it is larger than the sum of its proper divisors (10333027).

51665105 is a wasteful number, since it uses less digits than its factorization.

51665105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10333026.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 51665105 is about 7187.8442526254. The cubic root of 51665105 is about 372.4481077211.

The spelling of 51665105 in words is "fifty-one million, six hundred sixty-five thousand, one hundred five".