81427001 has 2 divisors, whose sum is σ = 81427002. Its totient is φ = 81427000.

The previous prime is 81426997. The next prime is 81427007. The reversal of 81427001 is 10072418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78943225 + 2483776 = 8885^2 + 1576^2 .

It is a cyclic number.

It is not a de Polignac number, because 81427001 - 2² = 81426997 is a prime.

It is not a weakly prime, because it can be changed into another prime (81427007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40713500 + 40713501.

It is an arithmetic number, because the mean of its divisors is an integer number (40713501).

Almost surely, 2^81427001 is an apocalyptic number.

It is an amenable number.

81427001 is a deficient number, since it is larger than the sum of its proper divisors (1).

81427001 is an equidigital number, since it uses as much as digits as its factorization.

81427001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 81427001 is about 9023.6910962200. The cubic root of 81427001 is about 433.4338377661.

Adding to 81427001 its reverse (10072418), we get a palindrome (91499419).

The spelling of 81427001 in words is "eighty-one million, four hundred twenty-seven thousand, one".