81524005 has 4 divisors (see below), whose sum is σ = 97828812. Its totient is φ = 65219200.

The previous prime is 81523973. The next prime is 81524021. The reversal of 81524005 is 50042518.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59490369 + 22033636 = 7713^2 + 4694^2 .

It is not a de Polignac number, because 81524005 - 2⁵ = 81523973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8152396 + ... + 8152405.

It is an arithmetic number, because the mean of its divisors is an integer number (24457203).

Almost surely, 2^81524005 is an apocalyptic number.

It is an amenable number.

81524005 is a deficient number, since it is larger than the sum of its proper divisors (16304807).

81524005 is a wasteful number, since it uses less digits than its factorization.

81524005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16304806.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 81524005 is about 9029.0644587355. The cubic root of 81524005 is about 433.6058860651.

The spelling of 81524005 in words is "eighty-one million, five hundred twenty-four thousand, five".