866131605 has 24 divisors (see below), whose sum is σ = 1502612280. Its totient is φ = 461531520.

The previous prime is 866131597. The next prime is 866131613. The reversal of 866131605 is 506131668.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (866131597) and next prime (866131613).

It can be written as a sum of positive squares in 4 ways, for example, as 614940804 + 251190801 = 24798^2 + 15849^2 .

It is not a de Polignac number, because 866131605 - 2³ = 866131597 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 866131605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47475 + ... + 63135.

It is an arithmetic number, because the mean of its divisors is an integer number (62608845).

Almost surely, 2^866131605 is an apocalyptic number.

It is an amenable number.

866131605 is a deficient number, since it is larger than the sum of its proper divisors (636480675).

866131605 is a wasteful number, since it uses less digits than its factorization.

866131605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16901 (or 16898 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 866131605 is about 29430.1139141526. The cubic root of 866131605 is about 953.2232545919.

The spelling of 866131605 in words is "eight hundred sixty-six million, one hundred thirty-one thousand, six hundred five".