81917206 has 16 divisors (see below), whose sum is σ = 141720480. Its totient is φ = 34784640.

The previous prime is 81917197. The next prime is 81917207. The reversal of 81917206 is 60271918.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81917207) 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, 25315 + ... + 28366.

It is an arithmetic number, because the mean of its divisors is an integer number (8857530).

Almost surely, 2^81917206 is an apocalyptic number.

81917206 is a deficient number, since it is larger than the sum of its proper divisors (59803274).

81917206 is a wasteful number, since it uses less digits than its factorization.

81917206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53799.

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

The square root of 81917206 is about 9050.8124497196. The cubic root of 81917206 is about 434.3018810451.

The spelling of 81917206 in words is "eighty-one million, nine hundred seventeen thousand, two hundred six".