81009305401 has 2 divisors, whose sum is σ = 81009305402. Its totient is φ = 81009305400.

The previous prime is 81009305381. The next prime is 81009305411. The reversal of 81009305401 is 10450390018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78531655225 + 2477650176 = 280235^2 + 49776^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81009305401 is a prime.

It is not a weakly prime, because it can be changed into another prime (81009305411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40504652700 + 40504652701.

It is an arithmetic number, because the mean of its divisors is an integer number (40504652701).

Almost surely, 2^81009305401 is an apocalyptic number.

It is an amenable number.

81009305401 is a deficient number, since it is larger than the sum of its proper divisors (1).

81009305401 is an equidigital number, since it uses as much as digits as its factorization.

81009305401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

Adding to 81009305401 its reverse (10450390018), we get a palindrome (91459695419).

The spelling of 81009305401 in words is "eighty-one billion, nine million, three hundred five thousand, four hundred one".