81537746120069 has 4 divisors (see below), whose sum is σ = 81571962549696. Its totient is φ = 81503529690444.

The previous prime is 81537746119997. The next prime is 81537746120141. The reversal of 81537746120069 is 96002164773518.

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 an interprime number because it is at equal distance from previous prime (81537746119997) and next prime (81537746120141).

It is a cyclic number.

It is not a de Polignac number, because 81537746120069 - 2⁸ = 81537746119813 is a prime.

It is a super-2 number, since 2×81537746120069² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81537746120669) 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, 17108211239 + ... + 17108216004.

It is an arithmetic number, because the mean of its divisors is an integer number (20392990637424).

It is a 2-persistent number, because it is pandigital, and so is 2⋅81537746120069 = 163075492240138, but 3⋅81537746120069 = 244613238360207 is not.

Almost surely, 2^{81537746120069} is an apocalyptic number.

It is an amenable number.

81537746120069 is a deficient number, since it is larger than the sum of its proper divisors (34216429627).

81537746120069 is a wasteful number, since it uses less digits than its factorization.

81537746120069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34216429626.

The product of its (nonzero) digits is 15240960, while the sum is 59.

The spelling of 81537746120069 in words is "eighty-one trillion, five hundred thirty-seven billion, seven hundred forty-six million, one hundred twenty thousand, sixty-nine".