81152409 has 16 divisors (see below), whose sum is σ = 119008512. Its totient is φ = 48876288.

The previous prime is 81152371. The next prime is 81152417. The reversal of 81152409 is 90425118.

It is a happy number.

It is not a de Polignac number, because 81152409 - 2¹² = 81148313 is a prime.

It is a super-3 number, since 3×81152409³ (a number of 25 digits) contains 333 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81152459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20304 + ... + 23969.

It is an arithmetic number, because the mean of its divisors is an integer number (7438032).

Almost surely, 2^81152409 is an apocalyptic number.

It is an amenable number.

81152409 is a deficient number, since it is larger than the sum of its proper divisors (37856103).

81152409 is a wasteful number, since it uses less digits than its factorization.

81152409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44336.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 81152409 is about 9008.4631874699. The cubic root of 81152409 is about 432.9460736765.

The spelling of 81152409 in words is "eighty-one million, one hundred fifty-two thousand, four hundred nine".