861626009 has 2 divisors, whose sum is σ = 861626010. Its totient is φ = 861626008.

The previous prime is 861625991. The next prime is 861626027. The reversal of 861626009 is 900626168.

It is a balanced prime because it is at equal distance from previous prime (861625991) and next prime (861626027).

It can be written as a sum of positive squares in only one way, i.e., 536617225 + 325008784 = 23165^2 + 18028^2 .

It is a cyclic number.

It is not a de Polignac number, because 861626009 - 2⁸ = 861625753 is a prime.

It is not a weakly prime, because it can be changed into another prime (861626089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430813004 + 430813005.

It is an arithmetic number, because the mean of its divisors is an integer number (430813005).

Almost surely, 2^861626009 is an apocalyptic number.

It is an amenable number.

861626009 is a deficient number, since it is larger than the sum of its proper divisors (1).

861626009 is an equidigital number, since it uses as much as digits as its factorization.

861626009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 861626009 is about 29353.4667288210. The cubic root of 861626009 is about 951.5674986336.

The spelling of 861626009 in words is "eight hundred sixty-one million, six hundred twenty-six thousand, nine".