51810681 has 8 divisors (see below), whose sum is σ = 74394880. Its totient is φ = 31883472.

The previous prime is 51810653. The next prime is 51810683. The reversal of 51810681 is 18601815.

It is a happy number.

51810681 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 51810681 - 2⁷ = 51810553 is a prime.

It is a super-2 number, since 2×51810681² = 5368693331367522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51810683) 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, 664201 + ... + 664278.

It is an arithmetic number, because the mean of its divisors is an integer number (9299360).

Almost surely, 2^51810681 is an apocalyptic number.

It is an amenable number.

51810681 is a deficient number, since it is larger than the sum of its proper divisors (22584199).

51810681 is a wasteful number, since it uses less digits than its factorization.

51810681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328495.

The product of its (nonzero) digits is 1920, while the sum is 30.

The square root of 51810681 is about 7197.9636703723. The cubic root of 51810681 is about 372.7975935155.

The spelling of 51810681 in words is "fifty-one million, eight hundred ten thousand, six hundred eighty-one".