81852705 has 96 divisors (see below), whose sum is σ = 167401728. Its totient is φ = 36556800.

The previous prime is 81852649. The next prime is 81852707. The reversal of 81852705 is 50725818.

It is not a de Polignac number, because 81852705 - 2¹² = 81848609 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81852705.

It is not an unprimeable number, because it can be changed into a prime (81852707) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 597397 + ... + 597533.

It is an arithmetic number, because the mean of its divisors is an integer number (1743768).

Almost surely, 2^81852705 is an apocalyptic number.

81852705 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81852705 is an abundant number, since it is smaller than the sum of its proper divisors (85549023).

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

81852705 is a wasteful number, since it uses less digits than its factorization.

81852705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 81852705 is about 9047.2484767469. The cubic root of 81852705 is about 434.1878624215.

The spelling of 81852705 in words is "eighty-one million, eight hundred fifty-two thousand, seven hundred five".