81206917 has 8 divisors (see below), whose sum is σ = 89080992. Its totient is φ = 73414800.

The previous prime is 81206903. The next prime is 81206947. The reversal of 81206917 is 71960218.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81206917 - 2⁷ = 81206789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81206947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18403 + ... + 22384.

It is an arithmetic number, because the mean of its divisors is an integer number (11135124).

Almost surely, 2^81206917 is an apocalyptic number.

It is an amenable number.

81206917 is a deficient number, since it is larger than the sum of its proper divisors (7874075).

81206917 is a wasteful number, since it uses less digits than its factorization.

81206917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40979.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 81206917 is about 9011.4880569193. The cubic root of 81206917 is about 433.0429849213.

The spelling of 81206917 in words is "eighty-one million, two hundred six thousand, nine hundred seventeen".