866455861 has 2 divisors, whose sum is σ = 866455862. Its totient is φ = 866455860.

The previous prime is 866455817. The next prime is 866455897. The reversal of 866455861 is 168554668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 816187761 + 50268100 = 28569^2 + 7090^2 .

It is a cyclic number.

It is not a de Polignac number, because 866455861 - 2¹³ = 866447669 is a prime.

It is a super-2 number, since 2×866455861² = 1501491518122502642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866455801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433227930 + 433227931.

It is an arithmetic number, because the mean of its divisors is an integer number (433227931).

Almost surely, 2^866455861 is an apocalyptic number.

It is an amenable number.

866455861 is a deficient number, since it is larger than the sum of its proper divisors (1).

866455861 is an equidigital number, since it uses as much as digits as its factorization.

866455861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1382400, while the sum is 49.

The square root of 866455861 is about 29435.6223137884. The cubic root of 866455861 is about 953.3421933284.

The spelling of 866455861 in words is "eight hundred sixty-six million, four hundred fifty-five thousand, eight hundred sixty-one".