81394164 has 72 divisors (see below), whose sum is σ = 219360960. Its totient is φ = 25358592.

The previous prime is 81394163. The next prime is 81394169. The reversal of 81394164 is 46149318.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81394163) 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 23 ways as a sum of consecutive naturals, for example, 109177 + ... + 109919.

It is an arithmetic number, because the mean of its divisors is an integer number (3046680).

Almost surely, 2^81394164 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81394164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109680480).

81394164 is an abundant number, since it is smaller than the sum of its proper divisors (137966796).

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

81394164 is a wasteful number, since it uses less digits than its factorization.

81394164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 949 (or 944 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 81394164 is about 9021.8714244884. The cubic root of 81394164 is about 433.3755664295.

The spelling of 81394164 in words is "eighty-one million, three hundred ninety-four thousand, one hundred sixty-four".