81123172930 has 16 divisors (see below), whose sum is σ = 146151759744. Its totient is φ = 32420369520.

The previous prime is 81123172913. The next prime is 81123172961. The reversal of 81123172930 is 3927132118.

It is a self number, because there is not a number n which added to its sum of digits gives 81123172930.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3600666 + ... + 3623125.

It is an arithmetic number, because the mean of its divisors is an integer number (9134484984).

Almost surely, 2^81123172930 is an apocalyptic number.

81123172930 is a deficient number, since it is larger than the sum of its proper divisors (65028586814).

81123172930 is a wasteful number, since it uses less digits than its factorization.

81123172930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7224921.

The product of its (nonzero) digits is 18144, while the sum is 37.

The spelling of 81123172930 in words is "eighty-one billion, one hundred twenty-three million, one hundred seventy-two thousand, nine hundred thirty".