51665501 has 4 divisors (see below), whose sum is σ = 53447100. Its totient is φ = 49883904.

The previous prime is 51665473. The next prime is 51665507. The reversal of 51665501 is 10556615.

51665501 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 37027225 + 14638276 = 6085^2 + 3826^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51665501 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 1781569 = 51665501 / (5 + 1 + 6 + 6 + 5 + 5 + 0 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51665507) 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 3 ways as a sum of consecutive naturals, for example, 890756 + ... + 890813.

It is an arithmetic number, because the mean of its divisors is an integer number (13361775).

Almost surely, 2^51665501 is an apocalyptic number.

It is an amenable number.

51665501 is a deficient number, since it is larger than the sum of its proper divisors (1781599).

51665501 is a wasteful number, since it uses less digits than its factorization.

51665501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1781598.

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

The square root of 51665501 is about 7187.8717990793. The cubic root of 51665501 is about 372.4490592923.

The spelling of 51665501 in words is "fifty-one million, six hundred sixty-five thousand, five hundred one".