81688606 has 8 divisors (see below), whose sum is σ = 124211664. Its totient is φ = 40284720.

The previous prime is 81688603. The next prime is 81688609. The reversal of 81688606 is 60688618.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81688603) and next prime (81688609).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81688603) 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, 279610 + ... + 279901.

It is an arithmetic number, because the mean of its divisors is an integer number (15526458).

Almost surely, 2^81688606 is an apocalyptic number.

81688606 is a deficient number, since it is larger than the sum of its proper divisors (42523058).

81688606 is a wasteful number, since it uses less digits than its factorization.

81688606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559586.

The product of its (nonzero) digits is 110592, while the sum is 43.

The square root of 81688606 is about 9038.1749263886. The cubic root of 81688606 is about 433.8975137959.

The spelling of 81688606 in words is "eighty-one million, six hundred eighty-eight thousand, six hundred six".