81141257 has 2 divisors, whose sum is σ = 81141258. Its totient is φ = 81141256.

The previous prime is 81141241. The next prime is 81141271. The reversal of 81141257 is 75214118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63027721 + 18113536 = 7939^2 + 4256^2 .

It is a cyclic number.

It is not a de Polignac number, because 81141257 - 2⁴ = 81141241 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81141287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40570628 + 40570629.

It is an arithmetic number, because the mean of its divisors is an integer number (40570629).

Almost surely, 2^81141257 is an apocalyptic number.

It is an amenable number.

81141257 is a deficient number, since it is larger than the sum of its proper divisors (1).

81141257 is an equidigital number, since it uses as much as digits as its factorization.

81141257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 29.

The square root of 81141257 is about 9007.8441927023. The cubic root of 81141257 is about 432.9262408876.

The spelling of 81141257 in words is "eighty-one million, one hundred forty-one thousand, two hundred fifty-seven".