81124012189 has 16 divisors (see below), whose sum is σ = 96727481856. Its totient is φ = 67171852800.

The previous prime is 81124012159. The next prime is 81124012201. The reversal of 81124012189 is 98121042118.

It is a cyclic number.

It is not a de Polignac number, because 81124012189 - 2¹³ = 81124003997 is a prime.

It is a super-2 number, since 2×81124012189² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81124012159) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 6991272 + ... + 7002865.

It is an arithmetic number, because the mean of its divisors is an integer number (6045467616).

Almost surely, 2^81124012189 is an apocalyptic number.

It is an amenable number.

81124012189 is a deficient number, since it is larger than the sum of its proper divisors (15603469667).

81124012189 is a wasteful number, since it uses less digits than its factorization.

81124012189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13994196.

The product of its (nonzero) digits is 9216, while the sum is 37.

The spelling of 81124012189 in words is "eighty-one billion, one hundred twenty-four million, twelve thousand, one hundred eighty-nine".