81211382 has 16 divisors (see below), whose sum is σ = 143711232. Its totient is φ = 33681960.

The previous prime is 81211379. The next prime is 81211387. The reversal of 81211382 is 28311218.

81211382 is a modest number, since divided by 11382 gives 812 as remainder.

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93128 + ... + 93995.

It is an arithmetic number, because the mean of its divisors is an integer number (8981952).

Almost surely, 2^81211382 is an apocalyptic number.

81211382 is a deficient number, since it is larger than the sum of its proper divisors (62499850).

81211382 is a wasteful number, since it uses less digits than its factorization.

81211382 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187163.

The product of its digits is 768, while the sum is 26.

The square root of 81211382 is about 9011.7357928426. The cubic root of 81211382 is about 433.0509214435.

The spelling of 81211382 in words is "eighty-one million, two hundred eleven thousand, three hundred eighty-two".