51551665 has 16 divisors (see below), whose sum is σ = 67677120. Its totient is φ = 37385920.

The previous prime is 51551657. The next prime is 51551683. The reversal of 51551665 is 56615515.

51551665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51551665 - 2³ = 51551657 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51551665.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 21927 + ... + 24163.

It is an arithmetic number, because the mean of its divisors is an integer number (4229820).

Almost surely, 2^51551665 is an apocalyptic number.

51551665 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51551665 is a deficient number, since it is larger than the sum of its proper divisors (16125455).

51551665 is a wasteful number, since it uses less digits than its factorization.

51551665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2672.

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

The square root of 51551665 is about 7179.9488159736. The cubic root of 51551665 is about 372.1753157727.

The spelling of 51551665 in words is "fifty-one million, five hundred fifty-one thousand, six hundred sixty-five".