81974517 has 8 divisors (see below), whose sum is σ = 111361824. Its totient is φ = 53618448.

The previous prime is 81974491. The next prime is 81974521. The reversal of 81974517 is 71547918.

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

It is not a de Polignac number, because 81974517 - 2¹⁴ = 81958133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81974537) 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, 257623 + ... + 257940.

It is an arithmetic number, because the mean of its divisors is an integer number (13920228).

Almost surely, 2^81974517 is an apocalyptic number.

It is an amenable number.

81974517 is a deficient number, since it is larger than the sum of its proper divisors (29387307).

81974517 is a wasteful number, since it uses less digits than its factorization.

81974517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515619.

The product of its digits is 70560, while the sum is 42.

The square root of 81974517 is about 9053.9779655133. The cubic root of 81974517 is about 434.4031396776.

The spelling of 81974517 in words is "eighty-one million, nine hundred seventy-four thousand, five hundred seventeen".