81494400 has 192 divisors, whose sum is σ = 289512720. Its totient is φ = 20029440.

The previous prime is 81494393. The next prime is 81494407. The reversal of 81494400 is 449418.

It is an interprime number because it is at equal distance from previous prime (81494393) and next prime (81494407).

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81494407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 124474 + ... + 125126.

Almost surely, 2^81494400 is an apocalyptic number.

81494400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81494400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144756360).

81494400 is an abundant number, since it is smaller than the sum of its proper divisors (208018320).

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

81494400 is a wasteful number, since it uses less digits than its factorization.

81494400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693 (or 676 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81494400 is about 9027.4248819915. The cubic root of 81494400 is about 433.5533925022.

The spelling of 81494400 in words is "eighty-one million, four hundred ninety-four thousand, four hundred".