8115661 has 2 divisors, whose sum is σ = 8115662. Its totient is φ = 8115660.

The previous prime is 8115659. The next prime is 8115671. The reversal of 8115661 is 1665118.

8115661 is nontrivially palindromic in base 11.

8115661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4622500 + 3493161 = 2150^2 + 1869^2 .

It is a cyclic number.

It is not a de Polignac number, because 8115661 - 2¹ = 8115659 is a prime.

Together with 8115659, it forms a pair of twin primes.

8115661 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8115671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4057830 + 4057831.

It is an arithmetic number, because the mean of its divisors is an integer number (4057831).

Almost surely, 2^8115661 is an apocalyptic number.

It is an amenable number.

8115661 is a deficient number, since it is larger than the sum of its proper divisors (1).

8115661 is an equidigital number, since it uses as much as digits as its factorization.

8115661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 28.

The square root of 8115661 is about 2848.7999227745. The cubic root of 8115661 is about 200.9592336654.

The spelling of 8115661 in words is "eight million, one hundred fifteen thousand, six hundred sixty-one".