81002506 has 8 divisors (see below), whose sum is σ = 130850244. Its totient is φ = 37385760.

The previous prime is 81002503. The next prime is 81002513. The reversal of 81002506 is 60520018.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 78163281 + 2839225 = 8841^2 + 1685^2 .

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

It is a super-2 number, since 2×81002506² = 13122811956560072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81002503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1557715 + ... + 1557766.

Almost surely, 2^81002506 is an apocalyptic number.

81002506 is a deficient number, since it is larger than the sum of its proper divisors (49847738).

81002506 is a wasteful number, since it uses less digits than its factorization.

81002506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3115496.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 81002506 is about 9000.1392211454. The cubic root of 81002506 is about 432.6793331171.

The spelling of 81002506 in words is "eighty-one million, two thousand, five hundred six".