81672985 has 8 divisors (see below), whose sum is σ = 98182656. Its totient is φ = 65221680.

The previous prime is 81672971. The next prime is 81672991. The reversal of 81672985 is 58927618.

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

It is a de Polignac number, because none of the positive numbers 2^k-81672985 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11449 + ... + 17158.

It is an arithmetic number, because the mean of its divisors is an integer number (12272832).

Almost surely, 2^81672985 is an apocalyptic number.

It is an amenable number.

81672985 is a deficient number, since it is larger than the sum of its proper divisors (16509671).

81672985 is a wasteful number, since it uses less digits than its factorization.

81672985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29183.

The product of its digits is 241920, while the sum is 46.

The square root of 81672985 is about 9037.3107172433. The cubic root of 81672985 is about 433.8698545115.

The spelling of 81672985 in words is "eighty-one million, six hundred seventy-two thousand, nine hundred eighty-five".