81143972870 has 16 divisors (see below), whose sum is σ = 151095674160. Its totient is φ = 31338361824.

The previous prime is 81143972831. The next prime is 81143972887. The reversal of 81143972870 is 7827934118.

It is a happy number.

It is a Curzon number.

It is a congruent number.

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, 139903112 + ... + 139903691.

It is an arithmetic number, because the mean of its divisors is an integer number (9443479635).

Almost surely, 2^81143972870 is an apocalyptic number.

81143972870 is a deficient number, since it is larger than the sum of its proper divisors (69951701290).

81143972870 is a wasteful number, since it uses less digits than its factorization.

81143972870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279806839.

The product of its (nonzero) digits is 677376, while the sum is 50.

The spelling of 81143972870 in words is "eighty-one billion, one hundred forty-three million, nine hundred seventy-two thousand, eight hundred seventy".