81770015782573 has 4 divisors (see below), whose sum is σ = 82890152985148. Its totient is φ = 80649878580000.

The previous prime is 81770015782571. The next prime is 81770015782619. The reversal of 81770015782573 is 37528751007718.

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 24573058522884 + 57196957259689 = 4957122^2 + 7562867^2 .

It is a cyclic number.

It is not a de Polignac number, because 81770015782573 - 2¹ = 81770015782571 is a prime.

It is a super-2 number, since 2×81770015782573² (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 (81770015782571) 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, 560068601178 + ... + 560068601323.

It is an arithmetic number, because the mean of its divisors is an integer number (20722538246287).

Almost surely, 2^{81770015782573} is an apocalyptic number.

It is an amenable number.

81770015782573 is a deficient number, since it is larger than the sum of its proper divisors (1120137202575).

81770015782573 is a wasteful number, since it uses less digits than its factorization.

81770015782573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1120137202574.

The product of its (nonzero) digits is 23049600, while the sum is 61.

The spelling of 81770015782573 in words is "eighty-one trillion, seven hundred seventy billion, fifteen million, seven hundred eighty-two thousand, five hundred seventy-three".