866394261 has 24 divisors (see below), whose sum is σ = 1268552376. Its totient is φ = 569750400.

The previous prime is 866394259. The next prime is 866394271. The reversal of 866394261 is 162493668.

866394261 is a `hidden beast` number, since 8 + 6 + 639 + 4 + 2 + 6 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 812592036 + 53802225 = 28506^2 + 7335^2 .

It is not a de Polignac number, because 866394261 - 2¹ = 866394259 is a prime.

It is a super-2 number, since 2×866394261² = 1501278030987472242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (866394241) 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, 264711 + ... + 267963.

It is an arithmetic number, because the mean of its divisors is an integer number (52856349).

Almost surely, 2^866394261 is an apocalyptic number.

It is an amenable number.

866394261 is a deficient number, since it is larger than the sum of its proper divisors (402158115).

866394261 is a wasteful number, since it uses less digits than its factorization.

866394261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3653 (or 3650 counting only the distinct ones).

The product of its digits is 373248, while the sum is 45.

The square root of 866394261 is about 29434.5759439473. The cubic root of 866394261 is about 953.3196004211.

The spelling of 866394261 in words is "eight hundred sixty-six million, three hundred ninety-four thousand, two hundred sixty-one".