866666040601 has 9 divisors (see below), whose sum is σ = 868671274653. Its totient is φ = 864665431200.

The previous prime is 866666040533. The next prime is 866666040649. The reversal of 866666040601 is 106040666668.

The square root of 866666040601 is 930949.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 37655790601 + 829010250000 = 194051^2 + 910500^2 .

It is not a de Polignac number, because 866666040601 - 2⁷ = 866666040473 is a prime.

It is a super-2 number, since 2×866666040601² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (866666041601) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 559499575 + ... + 559501123.

It is an arithmetic number, because the mean of its divisors is an integer number (96519030517).

Almost surely, 2^866666040601 is an apocalyptic number.

866666040601 is the 930949-th square number.

866666040601 is the 465475-th centered octagonal number.

It is an amenable number.

866666040601 is a deficient number, since it is larger than the sum of its proper divisors (2005234052).

866666040601 is an frugal number, since it uses more digits than its factorization.

866666040601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4300 (or 2150 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 49.

Multiplying 866666040601 by its sum of digits (49), we get a square (42466635989449 = 6516643²).

The spelling of 866666040601 in words is "eight hundred sixty-six billion, six hundred sixty-six million, forty thousand, six hundred one".