81724079516 has 12 divisors (see below), whose sum is σ = 143161462080. Its totient is φ = 40820804640.

The previous prime is 81724079491. The next prime is 81724079597. The reversal of 81724079516 is 61597042718.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10304321 + ... + 10312248.

It is an arithmetic number, because the mean of its divisors is an integer number (11930121840).

Almost surely, 2^81724079516 is an apocalyptic number.

It is an amenable number.

81724079516 is a deficient number, since it is larger than the sum of its proper divisors (61437382564).

81724079516 is a wasteful number, since it uses less digits than its factorization.

81724079516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20617564 (or 20617562 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 50.

The spelling of 81724079516 in words is "eighty-one billion, seven hundred twenty-four million, seventy-nine thousand, five hundred sixteen".