51988681 has 2 divisors, whose sum is σ = 51988682. Its totient is φ = 51988680.

The previous prime is 51988679. The next prime is 51988723. The reversal of 51988681 is 18688915.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32672656 + 19316025 = 5716^2 + 4395^2 .

It is a cyclic number.

It is not a de Polignac number, because 51988681 - 2¹ = 51988679 is a prime.

It is a super-2 number, since 2×51988681² = 5405645904239522, which contains 22 as substring.

Together with 51988679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51988621) 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 as a sum of consecutive naturals, namely, 25994340 + 25994341.

It is an arithmetic number, because the mean of its divisors is an integer number (25994341).

Almost surely, 2^51988681 is an apocalyptic number.

It is an amenable number.

51988681 is a deficient number, since it is larger than the sum of its proper divisors (1).

51988681 is an equidigital number, since it uses as much as digits as its factorization.

51988681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 138240, while the sum is 46.

The square root of 51988681 is about 7210.3176767740. The cubic root of 51988681 is about 373.2240314769.

The spelling of 51988681 in words is "fifty-one million, nine hundred eighty-eight thousand, six hundred eighty-one".