81247200 has 144 divisors (see below), whose sum is σ = 267951600. Its totient is φ = 21381120.

The previous prime is 81247193. The next prime is 81247213. The reversal of 81247200 is 274218.

It is a super-2 number, since 2×81247200² = 13202215015680000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 232626 + ... + 232974.

It is an arithmetic number, because the mean of its divisors is an integer number (1860775).

Almost surely, 2^81247200 is an apocalyptic number.

81247200 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 81247200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133975800).

81247200 is an abundant number, since it is smaller than the sum of its proper divisors (186704400).

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

81247200 is a wasteful number, since it uses less digits than its factorization.

81247200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469 (or 456 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 81247200 is about 9013.7228712669. The cubic root of 81247200 is about 433.1145772913.

The spelling of 81247200 in words is "eighty-one million, two hundred forty-seven thousand, two hundred".