81211384 has 16 divisors (see below), whose sum is σ = 152409600. Its totient is φ = 40568832.

The previous prime is 81211379. The next prime is 81211387. The reversal of 81211384 is 48311218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81211387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6264 + ... + 14200.

It is an arithmetic number, because the mean of its divisors is an integer number (9525600).

Almost surely, 2^81211384 is an apocalyptic number.

It is an amenable number.

81211384 is a deficient number, since it is larger than the sum of its proper divisors (71198216).

81211384 is a wasteful number, since it uses less digits than its factorization.

81211384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9222 (or 9218 counting only the distinct ones).

The product of its digits is 1536, while the sum is 28.

The square root of 81211384 is about 9011.7359038090. The cubic root of 81211384 is about 433.0509249984.

The spelling of 81211384 in words is "eighty-one million, two hundred eleven thousand, three hundred eighty-four".