81640313211 has 8 divisors (see below), whose sum is σ = 108863900224. Its totient is φ = 54421800840.

The previous prime is 81640313207. The next prime is 81640313219. The reversal of 81640313211 is 11231304618.

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

It is not a de Polignac number, because 81640313211 - 2² = 81640313207 is a prime.

It is a super-2 number, since 2×81640313211² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81640313219) 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, 1230961 + ... + 1295586.

It is an arithmetic number, because the mean of its divisors is an integer number (13607987528).

Almost surely, 2^81640313211 is an apocalyptic number.

81640313211 is a deficient number, since it is larger than the sum of its proper divisors (27223587013).

81640313211 is a wasteful number, since it uses less digits than its factorization.

81640313211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2537321.

The product of its (nonzero) digits is 3456, while the sum is 30.

Adding to 81640313211 its reverse (11231304618), we get a palindrome (92871617829).

The spelling of 81640313211 in words is "eighty-one billion, six hundred forty million, three hundred thirteen thousand, two hundred eleven".