80209999 has 4 divisors (see below), whose sum is σ = 80919936. Its totient is φ = 79500064.

The previous prime is 80209973. The next prime is 80210021. The reversal of 80209999 is 99990208.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 80209999 - 2⁵ = 80209967 is a prime.

It is a Duffinian number.

80209999 is a modest number, since divided by 9999 gives 8020 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80209919) 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, 354799 + ... + 355024.

It is an arithmetic number, because the mean of its divisors is an integer number (20229984).

Almost surely, 2^80209999 is an apocalyptic number.

80209999 is a deficient number, since it is larger than the sum of its proper divisors (709937).

80209999 is a wasteful number, since it uses less digits than its factorization.

80209999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709936.

The product of its (nonzero) digits is 104976, while the sum is 46.

The square root of 80209999 is about 8956.0035171945. The cubic root of 80209999 is about 431.2636328674.

The spelling of 80209999 in words is "eighty million, two hundred nine thousand, nine hundred ninety-nine".