55991603 has 2 divisors, whose sum is σ = 55991604. Its totient is φ = 55991602.

The previous prime is 55991599. The next prime is 55991669. The reversal of 55991603 is 30619955.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 55991603 - 2² = 55991599 is a prime.

It is not a weakly prime, because it can be changed into another prime (55991003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27995801 + 27995802.

It is an arithmetic number, because the mean of its divisors is an integer number (27995802).

Almost surely, 2^55991603 is an apocalyptic number.

55991603 is a deficient number, since it is larger than the sum of its proper divisors (1).

55991603 is an equidigital number, since it uses as much as digits as its factorization.

55991603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36450, while the sum is 38.

The square root of 55991603 is about 7482.7537043524. The cubic root of 55991603 is about 382.5671131187.

The spelling of 55991603 in words is "fifty-five million, nine hundred ninety-one thousand, six hundred three".