81322400 has 36 divisors (see below), whose sum is σ = 198530262. Its totient is φ = 32528640.

The previous prime is 81322357. The next prime is 81322427. The reversal of 81322400 is 422318.

It can be written as a sum of positive squares in 3 ways, for example, as 77651344 + 3671056 = 8812^2 + 1916^2 .

It is a super-2 number, since 2×81322400² = 13226665483520000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 50027 + ... + 51626.

Almost surely, 2^81322400 is an apocalyptic number.

81322400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81322400 is an abundant number, since it is smaller than the sum of its proper divisors (117207862).

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

81322400 is a wasteful number, since it uses less digits than its factorization.

81322400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101673 (or 101660 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 81322400 is about 9017.8933238312. The cubic root of 81322400 is about 433.2481620905.

Adding to 81322400 its reverse (422318), we get a palindrome (81744718).

The spelling of 81322400 in words is "eighty-one million, three hundred twenty-two thousand, four hundred".