111661609 has 2 divisors, whose sum is σ = 111661610. Its totient is φ = 111661608.

The previous prime is 111661601. The next prime is 111661637. The reversal of 111661609 is 906166111.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 104755225 + 6906384 = 10235^2 + 2628^2 .

It is a cyclic number.

It is not a de Polignac number, because 111661609 - 2³ = 111661601 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (111661601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55830804 + 55830805.

It is an arithmetic number, because the mean of its divisors is an integer number (55830805).

Almost surely, 2^111661609 is an apocalyptic number.

It is an amenable number.

111661609 is a deficient number, since it is larger than the sum of its proper divisors (1).

111661609 is an equidigital number, since it uses as much as digits as its factorization.

111661609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 111661609 is about 10567.0056780528. The cubic root of 111661609 is about 481.5425044978.

The spelling of 111661609 in words is "one hundred eleven million, six hundred sixty-one thousand, six hundred nine".