81768721930 has 32 divisors (see below), whose sum is σ = 168642414720. Its totient is φ = 27962911680.

The previous prime is 81768721921. The next prime is 81768721943. The reversal of 81768721930 is 3912786718.

It is a super-2 number, since 2×81768721930² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1474216 + ... + 1528675.

It is an arithmetic number, because the mean of its divisors is an integer number (5270075460).

Almost surely, 2^81768721930 is an apocalyptic number.

81768721930 is an abundant number, since it is smaller than the sum of its proper divisors (86873692790).

81768721930 is a wasteful number, since it uses less digits than its factorization.

81768721930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3003294.

The product of its (nonzero) digits is 1016064, while the sum is 52.

The spelling of 81768721930 in words is "eighty-one billion, seven hundred sixty-eight million, seven hundred twenty-one thousand, nine hundred thirty".