81033870281761 has 4 divisors (see below), whose sum is σ = 81033899185300. Its totient is φ = 81033841378224.

The previous prime is 81033870281759. The next prime is 81033870281779. The reversal of 81033870281761 is 16718207833018.

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 66458609406225 + 14575260875536 = 8152215^2 + 3817756^2 .

It is a cyclic number.

It is not a de Polignac number, because 81033870281761 - 2¹ = 81033870281759 is a prime.

It is a super-2 number, since 2×81033870281761² (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 (81033870287761) 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, 9732726 + ... + 16024783.

It is an arithmetic number, because the mean of its divisors is an integer number (20258474796325).

Almost surely, 2^{81033870281761} is an apocalyptic number.

It is an amenable number.

81033870281761 is a deficient number, since it is larger than the sum of its proper divisors (28903539).

81033870281761 is a wasteful number, since it uses less digits than its factorization.

81033870281761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28903538.

The product of its (nonzero) digits is 2709504, while the sum is 55.

The spelling of 81033870281761 in words is "eighty-one trillion, thirty-three billion, eight hundred seventy million, two hundred eighty-one thousand, seven hundred sixty-one".