81646640267 has 8 divisors (see below), whose sum is σ = 85951257600. Its totient is φ = 77342765544.

The previous prime is 81646640233. The next prime is 81646640269. The reversal of 81646640267 is 76204664618.

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 81646640267 - 2²⁶ = 81579531403 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81646640269) 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, 47558 + ... + 406884.

It is an arithmetic number, because the mean of its divisors is an integer number (10743907200).

Almost surely, 2^81646640267 is an apocalyptic number.

81646640267 is a deficient number, since it is larger than the sum of its proper divisors (4304617333).

81646640267 is a wasteful number, since it uses less digits than its factorization.

81646640267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371305.

The product of its (nonzero) digits is 2322432, while the sum is 50.

The spelling of 81646640267 in words is "eighty-one billion, six hundred forty-six million, six hundred forty thousand, two hundred sixty-seven".