866861761 has 2 divisors, whose sum is σ = 866861762. Its totient is φ = 866861760.

The previous prime is 866861657. The next prime is 866861767. The reversal of 866861761 is 167168668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 663371536 + 203490225 = 25756^2 + 14265^2 .

It is a cyclic number.

It is not a de Polignac number, because 866861761 - 2¹⁵ = 866828993 is a prime.

It is a super-2 number, since 2×866861761² = 1502898625368042242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (866861767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433430880 + 433430881.

It is an arithmetic number, because the mean of its divisors is an integer number (433430881).

Almost surely, 2^866861761 is an apocalyptic number.

It is an amenable number.

866861761 is a deficient number, since it is larger than the sum of its proper divisors (1).

866861761 is an equidigital number, since it uses as much as digits as its factorization.

866861761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 49.

The square root of 866861761 is about 29442.5162138021. The cubic root of 866861761 is about 953.4910376816.

The spelling of 866861761 in words is "eight hundred sixty-six million, eight hundred sixty-one thousand, seven hundred sixty-one".