80815909 has 4 divisors (see below), whose sum is σ = 85569804. Its totient is φ = 76062016.

The previous prime is 80815897. The next prime is 80815913. The reversal of 80815909 is 90951808.

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 41088100 + 39727809 = 6410^2 + 6303^2 .

It is a cyclic number.

It is not a de Polignac number, because 80815909 - 2²⁵ = 47261477 is a prime.

It is a super-2 number, since 2×80815909² = 13062422294992562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80815919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2376922 + ... + 2376955.

It is an arithmetic number, because the mean of its divisors is an integer number (21392451).

Almost surely, 2^80815909 is an apocalyptic number.

It is an amenable number.

80815909 is a deficient number, since it is larger than the sum of its proper divisors (4753895).

80815909 is a wasteful number, since it uses less digits than its factorization.

80815909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4753894.

The product of its (nonzero) digits is 25920, while the sum is 40.

The square root of 80815909 is about 8989.7669046533. The cubic root of 80815909 is about 432.3468383016.

The spelling of 80815909 in words is "eighty million, eight hundred fifteen thousand, nine hundred nine".