81394000 has 40 divisors (see below), whose sum is σ = 196815528. Its totient is φ = 32556800.

The previous prime is 81393997. The next prime is 81394009. The reversal of 81394000 is 49318.

It can be written as a sum of positive squares in 4 ways, for example, as 22963264 + 58430736 = 4792^2 + 7644^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81394009) 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, 18349 + ... + 22348.

Almost surely, 2^81394000 is an apocalyptic number.

81394000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81394000 is an abundant number, since it is smaller than the sum of its proper divisors (115421528).

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

81394000 is a wasteful number, since it uses less digits than its factorization.

81394000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40720 (or 40704 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 81394000 is about 9021.8623354605. The cubic root of 81394000 is about 433.3752753618.

The spelling of 81394000 in words is "eighty-one million, three hundred ninety-four thousand".