81212870126 has 4 divisors (see below), whose sum is σ = 121819305192. Its totient is φ = 40606435062.

The previous prime is 81212870117. The next prime is 81212870131. The reversal of 81212870126 is 62107821218.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81212870126.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20303217530 + ... + 20303217533.

It is an arithmetic number, because the mean of its divisors is an integer number (30454826298).

Almost surely, 2^81212870126 is an apocalyptic number.

81212870126 is a deficient number, since it is larger than the sum of its proper divisors (40606435066).

81212870126 is a wasteful number, since it uses less digits than its factorization.

81212870126 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40606435065.

The product of its (nonzero) digits is 21504, while the sum is 38.

The spelling of 81212870126 in words is "eighty-one billion, two hundred twelve million, eight hundred seventy thousand, one hundred twenty-six".