81000015 has 8 divisors (see below), whose sum is σ = 129600048. Its totient is φ = 43200000.

The previous prime is 81000013. The next prime is 81000037. The reversal of 81000015 is 51000018.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81000015 - 2¹ = 81000013 is a prime.

It is a super-2 number, since 2×81000015² = 13122004860000450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 5400001 = 81000015 / (8 + 1 + 0 + 0 + 0 + 0 + 1 + 5).

It is a junction number, because it is equal to n+sod(n) for n = 80999958 and 81000003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2699986 + ... + 2700015.

It is an arithmetic number, because the mean of its divisors is an integer number (16200006).

Almost surely, 2^81000015 is an apocalyptic number.

81000015 is a deficient number, since it is larger than the sum of its proper divisors (48600033).

81000015 is a wasteful number, since it uses less digits than its factorization.

81000015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5400009.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 81000015 is about 9000.0008333333. Note that the first 3 decimals coincide. The cubic root of 81000015 is about 432.6748978005.

Subtracting from 81000015 its sum of digits (15), we obtain a square (81000000 = 9000²).

The spelling of 81000015 in words is "eighty-one million, fifteen", and thus it is an aban number and an uban number.