81213665466 has 8 divisors (see below), whose sum is σ = 162427330944. Its totient is φ = 27071221820.

The previous prime is 81213665461. The next prime is 81213665471. The reversal of 81213665466 is 66456631218.

It is an interprime number because it is at equal distance from previous prime (81213665461) and next prime (81213665471).

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

81213665466 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (81213665461) 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, 6767805450 + ... + 6767805461.

It is an arithmetic number, because the mean of its divisors is an integer number (20303416368).

Almost surely, 2^81213665466 is an apocalyptic number.

81213665466 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81213665466 is a wasteful number, since it uses less digits than its factorization.

81213665466 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13535610916.

The product of its digits is 1244160, while the sum is 48.

The spelling of 81213665466 in words is "eighty-one billion, two hundred thirteen million, six hundred sixty-five thousand, four hundred sixty-six".