81326665553833 has 4 divisors (see below), whose sum is σ = 92944760632960. Its totient is φ = 69708570474708.

The previous prime is 81326665553773. The next prime is 81326665553863. The reversal of 81326665553833 is 33835556662318.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81326665553833 is a prime.

It is a super-2 number, since 2×81326665553833² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81326665553863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5809047539553 + ... + 5809047539566.

It is an arithmetic number, because the mean of its divisors is an integer number (23236190158240).

Almost surely, 2^{81326665553833} is an apocalyptic number.

It is an amenable number.

81326665553833 is a deficient number, since it is larger than the sum of its proper divisors (11618095079127).

81326665553833 is a wasteful number, since it uses less digits than its factorization.

81326665553833 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11618095079126.

The product of its digits is 279936000, while the sum is 64.

The spelling of 81326665553833 in words is "eighty-one trillion, three hundred twenty-six billion, six hundred sixty-five million, five hundred fifty-three thousand, eight hundred thirty-three".