81969834957945 has 48 divisors (see below), whose sum is σ = 144185267552256. Its totient is φ = 39735576179200.

The previous prime is 81969834957943. The next prime is 81969834957953. The reversal of 81969834957945 is 54975943896918.

It is not a de Polignac number, because 81969834957945 - 2¹ = 81969834957943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81969834957943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5601160 + ... + 13975430.

It is an arithmetic number, because the mean of its divisors is an integer number (3003859740672).

Almost surely, 2^{81969834957945} is an apocalyptic number.

It is an amenable number.

81969834957945 is a deficient number, since it is larger than the sum of its proper divisors (62215432594311).

81969834957945 is a wasteful number, since it uses less digits than its factorization.

81969834957945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8379694 (or 8379683 counting only the distinct ones).

The product of its digits is 21163161600, while the sum is 87.

The spelling of 81969834957945 in words is "eighty-one trillion, nine hundred sixty-nine billion, eight hundred thirty-four million, nine hundred fifty-seven thousand, nine hundred forty-five".