81609206 has 12 divisors (see below), whose sum is σ = 142399908. Its totient is φ = 34975332.

The previous prime is 81609193. The next prime is 81609217. The reversal of 81609206 is 60290618.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 416276 + ... + 416471.

It is an arithmetic number, because the mean of its divisors is an integer number (11866659).

Almost surely, 2^81609206 is an apocalyptic number.

81609206 is a deficient number, since it is larger than the sum of its proper divisors (60790702).

81609206 is a wasteful number, since it uses less digits than its factorization.

81609206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832763 (or 832756 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 81609206 is about 9033.7813788026. The cubic root of 81609206 is about 433.7568877755.

The spelling of 81609206 in words is "eighty-one million, six hundred nine thousand, two hundred six".