81688958 has 8 divisors (see below), whose sum is σ = 131959128. Its totient is φ = 37702584.

The previous prime is 81688909. The next prime is 81689033. The reversal of 81688958 is 85988618.

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

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 3 ways as a sum of consecutive naturals, for example, 1570916 + ... + 1570967.

It is an arithmetic number, because the mean of its divisors is an integer number (16494891).

Almost surely, 2^81688958 is an apocalyptic number.

81688958 is a deficient number, since it is larger than the sum of its proper divisors (50270170).

81688958 is a wasteful number, since it uses less digits than its factorization.

81688958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3141898.

The product of its digits is 1105920, while the sum is 53.

The square root of 81688958 is about 9038.1943993256. The cubic root of 81688958 is about 433.8981370232.

The spelling of 81688958 in words is "eighty-one million, six hundred eighty-eight thousand, nine hundred fifty-eight".