81168153533 has 8 divisors (see below), whose sum is σ = 81601942968. Its totient is φ = 80734500864.

The previous prime is 81168153503. The next prime is 81168153541. The reversal of 81168153533 is 33535186118.

It can be written as a sum of positive squares in 4 ways, for example, as 4121383204 + 77046770329 = 64198^2 + 277573^2 .

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 81168153533 - 2¹² = 81168149437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81168153503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1292735 + ... + 1354067.

It is an arithmetic number, because the mean of its divisors is an integer number (10200242871).

Almost surely, 2^81168153533 is an apocalyptic number.

It is an amenable number.

81168153533 is a deficient number, since it is larger than the sum of its proper divisors (433789435).

81168153533 is a wasteful number, since it uses less digits than its factorization.

81168153533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68383.

The product of its digits is 259200, while the sum is 44.

The spelling of 81168153533 in words is "eighty-one billion, one hundred sixty-eight million, one hundred fifty-three thousand, five hundred thirty-three".