55660991 has 2 divisors, whose sum is σ = 55660992. Its totient is φ = 55660990.

The previous prime is 55660981. The next prime is 55660993. The reversal of 55660991 is 19906655.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 55660991 - 2¹⁴ = 55644607 is a prime.

Together with 55660993, 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 (55660993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27830495 + 27830496.

It is an arithmetic number, because the mean of its divisors is an integer number (27830496).

Almost surely, 2^55660991 is an apocalyptic number.

55660991 is a deficient number, since it is larger than the sum of its proper divisors (1).

55660991 is an equidigital number, since it uses as much as digits as its factorization.

55660991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72900, while the sum is 41.

The square root of 55660991 is about 7460.6293970415. The cubic root of 55660991 is about 381.8126485507.

The spelling of 55660991 in words is "fifty-five million, six hundred sixty thousand, nine hundred ninety-one".