51563681 has 8 divisors (see below), whose sum is σ = 57031464. Its totient is φ = 46310400.

The previous prime is 51563671. The next prime is 51563693. The reversal of 51563681 is 18636515.

It can be written as a sum of positive squares in 4 ways, for example, as 1380625 + 50183056 = 1175^2 + 7084^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51563681 is a prime.

It is a super-2 number, since 2×51563681² = 5317626396539522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51563671) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 53120 + ... + 54081.

It is an arithmetic number, because the mean of its divisors is an integer number (7128933).

Almost surely, 2^51563681 is an apocalyptic number.

It is an amenable number.

51563681 is a deficient number, since it is larger than the sum of its proper divisors (5467783).

51563681 is a wasteful number, since it uses less digits than its factorization.

51563681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107251.

The product of its digits is 21600, while the sum is 35.

The square root of 51563681 is about 7180.7855419863. The cubic root of 51563681 is about 372.2042298804.

The spelling of 51563681 in words is "fifty-one million, five hundred sixty-three thousand, six hundred eighty-one".