81151200 has 432 divisors, whose sum is σ = 335759760. Its totient is φ = 18800640.

The previous prime is 81151159. The next prime is 81151201. The reversal of 81151200 is 215118.

It is a tau number, because it is divible by the number of its divisors (432).

It is a super-2 number, since 2×81151200² = 13171034522880000, 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 not an unprimeable number, because it can be changed into a prime (81151201) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 4773592 + ... + 4773608.

Almost surely, 2^81151200 is an apocalyptic number.

81151200 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 81151200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (167879880).

81151200 is an abundant number, since it is smaller than the sum of its proper divisors (254608560).

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

81151200 is a wasteful number, since it uses less digits than its factorization.

81151200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The square root of 81151200 is about 9008.3960836544. The cubic root of 81151200 is about 432.9439236709.

Adding to 81151200 its reverse (215118), we get a palindrome (81366318).

The spelling of 81151200 in words is "eighty-one million, one hundred fifty-one thousand, two hundred".