51665515 has 8 divisors (see below), whose sum is σ = 67634928. Its totient is φ = 37574880.

The previous prime is 51665507. The next prime is 51665519. The reversal of 51665515 is 51556615.

51665515 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 51665515 - 2³ = 51665507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51665519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 469632 + ... + 469741.

It is an arithmetic number, because the mean of its divisors is an integer number (8454366).

Almost surely, 2^51665515 is an apocalyptic number.

51665515 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51665515 is a deficient number, since it is larger than the sum of its proper divisors (15969413).

51665515 is a wasteful number, since it uses less digits than its factorization.

51665515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 939389.

The product of its digits is 22500, while the sum is 34.

The square root of 51665515 is about 7187.8727729419. The cubic root of 51665515 is about 372.4490929336.

Subtracting from 51665515 its reverse (51556615), we obtain a square (108900 = 330²).

It can be divided in two parts, 51 and 665515, that added together give a palindrome (665566).

The spelling of 51665515 in words is "fifty-one million, six hundred sixty-five thousand, five hundred fifteen".