81508561267 has 8 divisors (see below), whose sum is σ = 98632208736. Its totient is φ = 65754805632.

The previous prime is 81508561243. The next prime is 81508561271. The reversal of 81508561267 is 76216580518.

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 81508561267 - 2¹⁹ = 81508036979 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 81508561267.

It is not an unprimeable number, because it can be changed into a prime (81508561207) 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, 342472828 + ... + 342473065.

It is an arithmetic number, because the mean of its divisors is an integer number (12329026092).

Almost surely, 2^81508561267 is an apocalyptic number.

81508561267 is a deficient number, since it is larger than the sum of its proper divisors (17123647469).

81508561267 is a wasteful number, since it uses less digits than its factorization.

81508561267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684945917.

The product of its (nonzero) digits is 806400, while the sum is 49.

The spelling of 81508561267 in words is "eighty-one billion, five hundred eight million, five hundred sixty-one thousand, two hundred sixty-seven".