866761067521385 has 16 divisors (see below), whose sum is σ = 1070890435237392. Its totient is φ = 673062450816000.

The previous prime is 866761067521381. The next prime is 866761067521387. The reversal of 866761067521385 is 583125760167668.

It can be written as a sum of positive squares in 8 ways, for example, as 486126883984 + 866274940637401 = 697228^2 + 29432549^2 .

It is not a de Polignac number, because 866761067521385 - 2² = 866761067521381 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866761067521381) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10731184916 + ... + 10731265685.

It is an arithmetic number, because the mean of its divisors is an integer number (66930652202337).

Almost surely, 2^{866761067521385} is an apocalyptic number.

It is an amenable number.

866761067521385 is a deficient number, since it is larger than the sum of its proper divisors (204129367716007).

866761067521385 is a wasteful number, since it uses less digits than its factorization.

866761067521385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21462450844.

The product of its (nonzero) digits is 609638400, while the sum is 71.

The spelling of 866761067521385 in words is "eight hundred sixty-six trillion, seven hundred sixty-one billion, sixty-seven million, five hundred twenty-one thousand, three hundred eighty-five".