81249999999 has 16 divisors (see below), whose sum is σ = 123816503808. Its totient is φ = 46425953952.

The previous prime is 81249999977. The next prime is 81250000199. The reversal of 81249999999 is 99999994218.

It is not a de Polignac number, because 81249999999 - 2⁹ = 81249999487 is a prime.

81249999999 is a modest number, since divided by 999999 gives 81249 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81249999949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309694 + ... + 508340.

It is an arithmetic number, because the mean of its divisors is an integer number (7738531488).

Almost surely, 2^81249999999 is an apocalyptic number.

81249999999 is a deficient number, since it is larger than the sum of its proper divisors (42566503809).

81249999999 is a wasteful number, since it uses less digits than its factorization.

81249999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218134.

The product of its digits is 306110016, while the sum is 78.

The spelling of 81249999999 in words is "eighty-one billion, two hundred forty-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".