51049981 has 2 divisors, whose sum is σ = 51049982. Its totient is φ = 51049980.

The previous prime is 51049969. The next prime is 51050009. The reversal of 51049981 is 18994015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50893956 + 156025 = 7134^2 + 395^2 .

It is a cyclic number.

It is not a de Polignac number, because 51049981 - 2¹³ = 51041789 is a prime.

It is a super-2 number, since 2×51049981² = 5212201120200722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51049981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51049931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25524990 + 25524991.

It is an arithmetic number, because the mean of its divisors is an integer number (25524991).

Almost surely, 2^51049981 is an apocalyptic number.

It is an amenable number.

51049981 is a deficient number, since it is larger than the sum of its proper divisors (1).

51049981 is an equidigital number, since it uses as much as digits as its factorization.

51049981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 51049981 is about 7144.9269415439. The cubic root of 51049981 is about 370.9640818364.

The spelling of 51049981 in words is "fifty-one million, forty-nine thousand, nine hundred eighty-one".