81125602133 has 4 divisors (see below), whose sum is σ = 81130761228. Its totient is φ = 81120443040.

The previous prime is 81125602121. The next prime is 81125602171. The reversal of 81125602133 is 33120652118.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 66849653809 + 14275948324 = 258553^2 + 119482^2 .

It is a cyclic number.

It is not a de Polignac number, because 81125602133 - 2³⁶ = 12406125397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81125602133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81125602433) 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, 2555888 + ... + 2587433.

It is an arithmetic number, because the mean of its divisors is an integer number (20282690307).

Almost surely, 2^81125602133 is an apocalyptic number.

It is an amenable number.

81125602133 is a deficient number, since it is larger than the sum of its proper divisors (5159095).

81125602133 is a wasteful number, since it uses less digits than its factorization.

81125602133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5159094.

The product of its (nonzero) digits is 8640, while the sum is 32.

The spelling of 81125602133 in words is "eighty-one billion, one hundred twenty-five million, six hundred two thousand, one hundred thirty-three".