66555403 has 2 divisors, whose sum is σ = 66555404. Its totient is φ = 66555402.

The previous prime is 66555389. The next prime is 66555409. The reversal of 66555403 is 30455566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66555403 - 2⁵ = 66555371 is a prime.

It is not a weakly prime, because it can be changed into another prime (66555409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33277701 + 33277702.

It is an arithmetic number, because the mean of its divisors is an integer number (33277702).

Almost surely, 2^66555403 is an apocalyptic number.

66555403 is a deficient number, since it is larger than the sum of its proper divisors (1).

66555403 is an equidigital number, since it uses as much as digits as its factorization.

66555403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54000, while the sum is 34.

The square root of 66555403 is about 8158.1494837984. The cubic root of 66555403 is about 405.2544313978.

The spelling of 66555403 in words is "sixty-six million, five hundred fifty-five thousand, four hundred three".