51751981 has 2 divisors, whose sum is σ = 51751982. Its totient is φ = 51751980.

The previous prime is 51751967. The next prime is 51751993. The reversal of 51751981 is 18915715.

51751981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46648900 + 5103081 = 6830^2 + 2259^2 .

It is a cyclic number.

It is not a de Polignac number, because 51751981 - 2⁵ = 51751949 is a prime.

It is a super-2 number, since 2×51751981² = 5356535074848722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 51751981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51751901) 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 as a sum of consecutive naturals, namely, 25875990 + 25875991.

It is an arithmetic number, because the mean of its divisors is an integer number (25875991).

Almost surely, 2^51751981 is an apocalyptic number.

It is an amenable number.

51751981 is a deficient number, since it is larger than the sum of its proper divisors (1).

51751981 is an equidigital number, since it uses as much as digits as its factorization.

51751981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12600, while the sum is 37.

The square root of 51751981 is about 7193.8849726695. The cubic root of 51751981 is about 372.6567506888.

The spelling of 51751981 in words is "fifty-one million, seven hundred fifty-one thousand, nine hundred eighty-one".