810380861 has 2 divisors, whose sum is σ = 810380862. Its totient is φ = 810380860.

The previous prime is 810380821. The next prime is 810380863. The reversal of 810380861 is 168083018.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 666620761 + 143760100 = 25819^2 + 11990^2 .

It is a cyclic number.

It is not a de Polignac number, because 810380861 - 2⁶ = 810380797 is a prime.

Together with 810380863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (810380863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405190430 + 405190431.

It is an arithmetic number, because the mean of its divisors is an integer number (405190431).

Almost surely, 2^810380861 is an apocalyptic number.

It is an amenable number.

810380861 is a deficient number, since it is larger than the sum of its proper divisors (1).

810380861 is an equidigital number, since it uses as much as digits as its factorization.

810380861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 810380861 is about 28467.1892009029. The cubic root of 810380861 is about 932.3158305820.

The spelling of 810380861 in words is "eight hundred ten million, three hundred eighty thousand, eight hundred sixty-one".