866039261 has 2 divisors, whose sum is σ = 866039262. Its totient is φ = 866039260.

The previous prime is 866039243. The next prime is 866039311. The reversal of 866039261 is 162930668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641608900 + 224430361 = 25330^2 + 14981^2 .

It is a cyclic number.

It is not a de Polignac number, because 866039261 - 2²² = 861844957 is a prime.

It is a super-2 number, since 2×866039261² = 1500048003186852242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866039231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433019630 + 433019631.

It is an arithmetic number, because the mean of its divisors is an integer number (433019631).

Almost surely, 2^866039261 is an apocalyptic number.

It is an amenable number.

866039261 is a deficient number, since it is larger than the sum of its proper divisors (1).

866039261 is an equidigital number, since it uses as much as digits as its factorization.

866039261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 41.

The square root of 866039261 is about 29428.5450031088. The cubic root of 866039261 is about 953.1893769162.

The spelling of 866039261 in words is "eight hundred sixty-six million, thirty-nine thousand, two hundred sixty-one".