81667917 has 24 divisors (see below), whose sum is σ = 126432384. Its totient is φ = 50665824.

The previous prime is 81667903. The next prime is 81667931. The reversal of 81667917 is 71976618.

It is an interprime number because it is at equal distance from previous prime (81667903) and next prime (81667931).

It is not a de Polignac number, because 81667917 - 2⁶ = 81667853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81667517) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2328 + ... + 12990.

It is an arithmetic number, because the mean of its divisors is an integer number (5268016).

Almost surely, 2^81667917 is an apocalyptic number.

It is an amenable number.

81667917 is a deficient number, since it is larger than the sum of its proper divisors (44764467).

81667917 is a wasteful number, since it uses less digits than its factorization.

81667917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10729 (or 10726 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 81667917 is about 9037.0303197455. The cubic root of 81667917 is about 433.8608801124.

The spelling of 81667917 in words is "eighty-one million, six hundred sixty-seven thousand, nine hundred seventeen".