81066240 has 216 divisors, whose sum is σ = 290803968. Its totient is φ = 20828160.

The previous prime is 81066239. The next prime is 81066241. The reversal of 81066240 is 4266018.

It is an interprime number because it is at equal distance from previous prime (81066239) and next prime (81066241).

It is not an unprimeable number, because it can be changed into a prime (81066241) 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 23 ways as a sum of consecutive naturals, for example, 357007 + ... + 357233.

Almost surely, 2^81066240 is an apocalyptic number.

81066240 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 81066240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145401984).

81066240 is an abundant number, since it is smaller than the sum of its proper divisors (209737728).

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

81066240 is a wasteful number, since it uses less digits than its factorization.

81066240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 81066240 is about 9003.6792479519. The cubic root of 81066240 is about 432.7927829210.

The spelling of 81066240 in words is "eighty-one million, sixty-six thousand, two hundred forty".