51155665 has 16 divisors (see below), whose sum is σ = 67568256. Its totient is φ = 36870400.

The previous prime is 51155641. The next prime is 51155677. The reversal of 51155665 is 56655115.

It is not a de Polignac number, because 51155665 - 2⁵ = 51155633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51155665.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2100 + ... + 10330.

It is an arithmetic number, because the mean of its divisors is an integer number (4223016).

Almost surely, 2^51155665 is an apocalyptic number.

51155665 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

It is an amenable number.

51155665 is a deficient number, since it is larger than the sum of its proper divisors (16412591).

51155665 is a wasteful number, since it uses less digits than its factorization.

51155665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8360.

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

The square root of 51155665 is about 7152.3188547491. The cubic root of 51155665 is about 371.2198961332.

The spelling of 51155665 in words is "fifty-one million, one hundred fifty-five thousand, six hundred sixty-five".