81207407209 has 8 divisors (see below), whose sum is σ = 84097346760. Its totient is φ = 78323446656.

The previous prime is 81207407207. The next prime is 81207407233. The reversal of 81207407209 is 90270470218.

It can be written as a sum of positive squares in 4 ways, for example, as 903182809 + 80304224400 = 30053^2 + 283380^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81207407209 - 2¹ = 81207407207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81207407207) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1467094 + ... + 1521439.

It is an arithmetic number, because the mean of its divisors is an integer number (10512168345).

Almost surely, 2^81207407209 is an apocalyptic number.

It is an amenable number.

81207407209 is a deficient number, since it is larger than the sum of its proper divisors (2889939551).

81207407209 is a wasteful number, since it uses less digits than its factorization.

81207407209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2989499.

The product of its (nonzero) digits is 56448, while the sum is 40.

The spelling of 81207407209 in words is "eighty-one billion, two hundred seven million, four hundred seven thousand, two hundred nine".