66649403 has 2 divisors, whose sum is σ = 66649404. Its totient is φ = 66649402.

The previous prime is 66649399. The next prime is 66649421. The reversal of 66649403 is 30494666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66649403 - 2² = 66649399 is a prime.

It is not a weakly prime, because it can be changed into another prime (66649433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33324701 + 33324702.

It is an arithmetic number, because the mean of its divisors is an integer number (33324702).

Almost surely, 2^66649403 is an apocalyptic number.

66649403 is a deficient number, since it is larger than the sum of its proper divisors (1).

66649403 is an equidigital number, since it uses as much as digits as its factorization.

66649403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 66649403 is about 8163.9085614674. The cubic root of 66649403 is about 405.4451296473.

The spelling of 66649403 in words is "sixty-six million, six hundred forty-nine thousand, four hundred three".