81649767143 has 16 divisors (see below), whose sum is σ = 99677459520. Its totient is φ = 65285799936.

The previous prime is 81649767139. The next prime is 81649767163. The reversal of 81649767143 is 34176794618.

It is not a de Polignac number, because 81649767143 - 2² = 81649767139 is a prime.

It is a super-2 number, since 2×81649767143² (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 (81649767103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3022538 + ... + 3049431.

It is an arithmetic number, because the mean of its divisors is an integer number (6229841220).

Almost surely, 2^81649767143 is an apocalyptic number.

81649767143 is a deficient number, since it is larger than the sum of its proper divisors (18027692377).

81649767143 is a wasteful number, since it uses less digits than its factorization.

81649767143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6072106.

The product of its digits is 6096384, while the sum is 56.

The spelling of 81649767143 in words is "eighty-one billion, six hundred forty-nine million, seven hundred sixty-seven thousand, one hundred forty-three".