81959170961 has 8 divisors (see below), whose sum is σ = 84801957480. Its totient is φ = 79117491712.

The previous prime is 81959170957. The next prime is 81959170999. The reversal of 81959170961 is 16907195918.

It can be written as a sum of positive squares in 4 ways, for example, as 2885730961 + 79073440000 = 53719^2 + 281200^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81959170961 - 2² = 81959170957 is a prime.

It is a super-2 number, since 2×81959170961² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81959170897 and 81959170906.

It is not an unprimeable number, because it can be changed into a prime (81959170661) 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 7 ways as a sum of consecutive naturals, for example, 124790 + ... + 423663.

It is an arithmetic number, because the mean of its divisors is an integer number (10600244685).

Almost surely, 2^81959170961 is an apocalyptic number.

It is an amenable number.

81959170961 is a deficient number, since it is larger than the sum of its proper divisors (2842786519).

81959170961 is a wasteful number, since it uses less digits than its factorization.

81959170961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553635.

The product of its (nonzero) digits is 1224720, while the sum is 56.

The spelling of 81959170961 in words is "eighty-one billion, nine hundred fifty-nine million, one hundred seventy thousand, nine hundred sixty-one".