81002985 has 48 divisors (see below), whose sum is σ = 156398976. Its totient is φ = 35064576.

The previous prime is 81002983. The next prime is 81002989. The reversal of 81002985 is 58920018.

It is a happy number.

It is not a de Polignac number, because 81002985 - 2¹ = 81002983 is a prime.

It is a super-2 number, since 2×81002985² = 13122967157820450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81002981) 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 47 ways as a sum of consecutive naturals, for example, 36837 + ... + 38973.

It is an arithmetic number, because the mean of its divisors is an integer number (3258312).

Almost surely, 2^81002985 is an apocalyptic number.

It is an amenable number.

81002985 is a deficient number, since it is larger than the sum of its proper divisors (75395991).

81002985 is a wasteful number, since it uses less digits than its factorization.

81002985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2190 (or 2171 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 81002985 is about 9000.1658318055. The cubic root of 81002985 is about 432.6801859837.

The spelling of 81002985 in words is "eighty-one million, two thousand, nine hundred eighty-five".