81417609 has 48 divisors (see below), whose sum is σ = 149328000. Its totient is φ = 42928704.

The previous prime is 81417599. The next prime is 81417643. The reversal of 81417609 is 90671418.

81417609 is a `hidden beast` number, since 8 + 1 + 41 + 7 + 609 = 666.

It is not a de Polignac number, because 81417609 - 2⁵ = 81417577 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81417209) 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 47 ways as a sum of consecutive naturals, for example, 30667 + ... + 33215.

It is an arithmetic number, because the mean of its divisors is an integer number (3111000).

Almost surely, 2^81417609 is an apocalyptic number.

It is an amenable number.

81417609 is a deficient number, since it is larger than the sum of its proper divisors (67910391).

81417609 is a wasteful number, since it uses less digits than its factorization.

81417609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2591 (or 2572 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 81417609 is about 9023.1706733276. The cubic root of 81417609 is about 433.4171726670.

The spelling of 81417609 in words is "eighty-one million, four hundred seventeen thousand, six hundred nine".