55666909 has 2 divisors, whose sum is σ = 55666910. Its totient is φ = 55666908.

The previous prime is 55666901. The next prime is 55666939. The reversal of 55666909 is 90966655.

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., 46648900 + 9018009 = 6830^2 + 3003^2 .

It is a cyclic number.

It is not a de Polignac number, because 55666909 - 2³ = 55666901 is a prime.

It is a super-2 number, since 2×55666909² = 6197609515228562, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55666901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27833454 + 27833455.

It is an arithmetic number, because the mean of its divisors is an integer number (27833455).

Almost surely, 2^55666909 is an apocalyptic number.

It is an amenable number.

55666909 is a deficient number, since it is larger than the sum of its proper divisors (1).

55666909 is an equidigital number, since it uses as much as digits as its factorization.

55666909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 437400, while the sum is 46.

The square root of 55666909 is about 7461.0260018311. The cubic root of 55666909 is about 381.8261797936.

The spelling of 55666909 in words is "fifty-five million, six hundred sixty-six thousand, nine hundred nine".