81050251 has 2 divisors, whose sum is σ = 81050252. Its totient is φ = 81050250.

The previous prime is 81050209. The next prime is 81050261. The reversal of 81050251 is 15205018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81050251 - 2⁹ = 81049739 is a prime.

It is not a weakly prime, because it can be changed into another prime (81050201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40525125 + 40525126.

It is an arithmetic number, because the mean of its divisors is an integer number (40525126).

Almost surely, 2^81050251 is an apocalyptic number.

81050251 is a deficient number, since it is larger than the sum of its proper divisors (1).

81050251 is an equidigital number, since it uses as much as digits as its factorization.

81050251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 400, while the sum is 22.

The square root of 81050251 is about 9002.7912893724. The cubic root of 81050251 is about 432.7643272663.

Adding to 81050251 its reverse (15205018), we get a palindrome (96255269).

The spelling of 81050251 in words is "eighty-one million, fifty thousand, two hundred fifty-one".