8461808581 has 2 divisors, whose sum is σ = 8461808582. Its totient is φ = 8461808580.

The previous prime is 8461808569. The next prime is 8461808603. The reversal of 8461808581 is 1858081648.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5945181025 + 2516627556 = 77105^2 + 50166^2 .

It is a cyclic number.

It is not a de Polignac number, because 8461808581 - 2¹⁵ = 8461775813 is a prime.

It is a super-2 number, since 2×8461808581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8461808521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4230904290 + 4230904291.

It is an arithmetic number, because the mean of its divisors is an integer number (4230904291).

Almost surely, 2^8461808581 is an apocalyptic number.

It is an amenable number.

8461808581 is a deficient number, since it is larger than the sum of its proper divisors (1).

8461808581 is an equidigital number, since it uses as much as digits as its factorization.

8461808581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 491520, while the sum is 49.

The square root of 8461808581 is about 91988.0893431318. The cubic root of 8461808581 is about 2037.7664087444.

The spelling of 8461808581 in words is "eight billion, four hundred sixty-one million, eight hundred eight thousand, five hundred eighty-one".