851042981 has 2 divisors, whose sum is σ = 851042982. Its totient is φ = 851042980.

The previous prime is 851042947. The next prime is 851043013. The reversal of 851042981 is 189240158.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 549152356 + 301890625 = 23434^2 + 17375^2 .

It is a cyclic number.

It is not a de Polignac number, because 851042981 - 2⁶ = 851042917 is a prime.

It is a super-2 number, since 2×851042981² = 1448548311018732722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (851042081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 425521490 + 425521491.

It is an arithmetic number, because the mean of its divisors is an integer number (425521491).

Almost surely, 2^851042981 is an apocalyptic number.

It is an amenable number.

851042981 is a deficient number, since it is larger than the sum of its proper divisors (1).

851042981 is an equidigital number, since it uses as much as digits as its factorization.

851042981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23040, while the sum is 38.

The square root of 851042981 is about 29172.6409671802. The cubic root of 851042981 is about 947.6555230493.

The spelling of 851042981 in words is "eight hundred fifty-one million, forty-two thousand, nine hundred eighty-one".