81211383 has 32 divisors (see below), whose sum is σ = 131865600. Its totient is φ = 48988800.

The previous prime is 81211379. The next prime is 81211387. The reversal of 81211383 is 38311218.

It is an interprime number because it is at equal distance from previous prime (81211379) and next prime (81211387).

It is not a de Polignac number, because 81211383 - 2² = 81211379 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79983 + ... + 80991.

It is an arithmetic number, because the mean of its divisors is an integer number (4120800).

Almost surely, 2^81211383 is an apocalyptic number.

81211383 is a deficient number, since it is larger than the sum of its proper divisors (50654217).

81211383 is a wasteful number, since it uses less digits than its factorization.

81211383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1300 (or 1294 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 81211383 is about 9011.7358483258. The cubic root of 81211383 is about 433.0509232210.

The spelling of 81211383 in words is "eighty-one million, two hundred eleven thousand, three hundred eighty-three".