866670996581 has 24 divisors (see below), whose sum is σ = 947308955976. Its totient is φ = 792474009600.

The previous prime is 866670996557. The next prime is 866670996589. The reversal of 866670996581 is 185699076668.

It can be written as a sum of positive squares in 12 ways, for example, as 866667902500 + 3094081 = 930950^2 + 1759^2 .

It is not a de Polignac number, because 866670996581 - 2²⁶ = 866603887717 is a prime.

It is a super-2 number, since 2×866670996581² (a number of 25 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 (866670996589) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36291461 + ... + 36315333.

It is an arithmetic number, because the mean of its divisors is an integer number (39471206499).

Almost surely, 2^866670996581 is an apocalyptic number.

It is an amenable number.

866670996581 is a deficient number, since it is larger than the sum of its proper divisors (80637959395).

866670996581 is a wasteful number, since it uses less digits than its factorization.

866670996581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25913 (or 25900 counting only the distinct ones).

The product of its (nonzero) digits is 235146240, while the sum is 71.

The spelling of 866670996581 in words is "eight hundred sixty-six billion, six hundred seventy million, nine hundred ninety-six thousand, five hundred eighty-one".