81764917 has 16 divisors (see below), whose sum is σ = 93562560. Its totient is φ = 70785792.

The previous prime is 81764911. The next prime is 81764941. The reversal of 81764917 is 71946718.

It is a cyclic number.

It is not a de Polignac number, because 81764917 - 2³ = 81764909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81764911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92158 + ... + 93040.

It is an arithmetic number, because the mean of its divisors is an integer number (5847660).

Almost surely, 2^81764917 is an apocalyptic number.

It is an amenable number.

81764917 is a deficient number, since it is larger than the sum of its proper divisors (11797643).

81764917 is a wasteful number, since it uses less digits than its factorization.

81764917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332.

The product of its digits is 84672, while the sum is 43.

The square root of 81764917 is about 9042.3955343703. The cubic root of 81764917 is about 434.0325830125.

The spelling of 81764917 in words is "eighty-one million, seven hundred sixty-four thousand, nine hundred seventeen".