81825451 has 2 divisors, whose sum is σ = 81825452. Its totient is φ = 81825450.

The previous prime is 81825439. The next prime is 81825473. The reversal of 81825451 is 15452818.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81825451 - 2¹³ = 81817259 is a prime.

It is not a weakly prime, because it can be changed into another prime (81825551) 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, 40912725 + 40912726.

It is an arithmetic number, because the mean of its divisors is an integer number (40912726).

Almost surely, 2^81825451 is an apocalyptic number.

81825451 is a deficient number, since it is larger than the sum of its proper divisors (1).

81825451 is an equidigital number, since it uses as much as digits as its factorization.

81825451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12800, while the sum is 34.

The square root of 81825451 is about 9045.7421475521. The cubic root of 81825451 is about 434.1396674368.

The spelling of 81825451 in words is "eighty-one million, eight hundred twenty-five thousand, four hundred fifty-one".