81317389724 has 12 divisors (see below), whose sum is σ = 146895930048. Its totient is φ = 39347124000.

The previous prime is 81317389717. The next prime is 81317389759. The reversal of 81317389724 is 42798371318.

It is a super-2 number, since 2×81317389724² (a number of 23 digits) contains 22 as substring.

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, 327892577 + ... + 327892824.

It is an arithmetic number, because the mean of its divisors is an integer number (12241327504).

Almost surely, 2^81317389724 is an apocalyptic number.

It is an amenable number.

81317389724 is a deficient number, since it is larger than the sum of its proper divisors (65578540324).

81317389724 is a wasteful number, since it uses less digits than its factorization.

81317389724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655785436 (or 655785434 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 53.

The spelling of 81317389724 in words is "eighty-one billion, three hundred seventeen million, three hundred eighty-nine thousand, seven hundred twenty-four".