81672145 has 8 divisors (see below), whose sum is σ = 98066880. Its totient is φ = 65297520.

The previous prime is 81672133. The next prime is 81672161. The reversal of 81672145 is 54127618.

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

It is not a de Polignac number, because 81672145 - 2⁵ = 81672113 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81672145.

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, 6190 + ... + 14200.

It is an arithmetic number, because the mean of its divisors is an integer number (12258360).

Almost surely, 2^81672145 is an apocalyptic number.

It is an amenable number.

81672145 is a deficient number, since it is larger than the sum of its proper divisors (16394735).

81672145 is a wasteful number, since it uses less digits than its factorization.

81672145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10055.

The product of its digits is 13440, while the sum is 34.

The square root of 81672145 is about 9037.2642431214. The cubic root of 81672145 is about 433.8683670677.

The spelling of 81672145 in words is "eighty-one million, six hundred seventy-two thousand, one hundred forty-five".