81396581801 has 4 divisors (see below), whose sum is σ = 81656635092. Its totient is φ = 81136528512.

The previous prime is 81396581789. The next prime is 81396581813. The reversal of 81396581801 is 10818569318.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (81396581789) and next prime (81396581813).

It can be written as a sum of positive squares in 2 ways, for example, as 21126331801 + 60270250000 = 145349^2 + 245500^2 .

It is a cyclic number.

It is not a de Polignac number, because 81396581801 - 2⁶ = 81396581737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81396581801.

It is not an unprimeable number, because it can be changed into a prime (81396581821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130026176 + ... + 130026801.

It is an arithmetic number, because the mean of its divisors is an integer number (20414158773).

Almost surely, 2^81396581801 is an apocalyptic number.

It is an amenable number.

81396581801 is a deficient number, since it is larger than the sum of its proper divisors (260053291).

81396581801 is a wasteful number, since it uses less digits than its factorization.

81396581801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260053290.

The product of its (nonzero) digits is 414720, while the sum is 50.

The spelling of 81396581801 in words is "eighty-one billion, three hundred ninety-six million, five hundred eighty-one thousand, eight hundred one".