81467209 has 4 divisors (see below), whose sum is σ = 81599440. Its totient is φ = 81334980.

The previous prime is 81467203. The next prime is 81467227. The reversal of 81467209 is 90276418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81467209 - 2¹⁷ = 81336137 is a prime.

It is a super-2 number, since 2×81467209² = 13273812284499362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81467203) 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, 65187 + ... + 66424.

It is an arithmetic number, because the mean of its divisors is an integer number (20399860).

Almost surely, 2^81467209 is an apocalyptic number.

It is an amenable number.

81467209 is a deficient number, since it is larger than the sum of its proper divisors (132231).

81467209 is a wasteful number, since it uses less digits than its factorization.

81467209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132230.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 81467209 is about 9025.9187344004. The cubic root of 81467209 is about 433.5051680775.

The spelling of 81467209 in words is "eighty-one million, four hundred sixty-seven thousand, two hundred nine".