81212516 has 24 divisors (see below), whose sum is σ = 177191616. Its totient is φ = 31641120.

The previous prime is 81212507. The next prime is 81212561. The reversal of 81212516 is 61521218.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131531 + ... + 132146.

It is an arithmetic number, because the mean of its divisors is an integer number (7382984).

Almost surely, 2^81212516 is an apocalyptic number.

It is an amenable number.

81212516 is an abundant number, since it is smaller than the sum of its proper divisors (95979100).

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

81212516 is a wasteful number, since it uses less digits than its factorization.

81212516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263699 (or 263697 counting only the distinct ones).

The product of its digits is 960, while the sum is 26.

The square root of 81212516 is about 9011.7987105794. The cubic root of 81212516 is about 433.0529370783.

The spelling of 81212516 in words is "eighty-one million, two hundred twelve thousand, five hundred sixteen".