81302400 has 192 divisors, whose sum is σ = 297860400. Its totient is φ = 21657600.

The previous prime is 81302383. The next prime is 81302453. The reversal of 81302400 is 420318.

It is a happy number.

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

It is a super-2 number, since 2×81302400² = 13220160491520000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 85930 + ... + 86870.

Almost surely, 2^81302400 is an apocalyptic number.

81302400 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 81302400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148930200).

81302400 is an abundant number, since it is smaller than the sum of its proper divisors (216558000).

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

81302400 is a wasteful number, since it uses less digits than its factorization.

81302400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 974 (or 951 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 81302400 is about 9016.7843492012. The cubic root of 81302400 is about 433.2126422596.

Adding to 81302400 its reverse (420318), we get a palindrome (81722718).

The spelling of 81302400 in words is "eighty-one million, three hundred two thousand, four hundred".