66628571 has 2 divisors, whose sum is σ = 66628572. Its totient is φ = 66628570.

The previous prime is 66628553. The next prime is 66628591. The reversal of 66628571 is 17582666.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66628571 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (66628591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33314285 + 33314286.

It is an arithmetic number, because the mean of its divisors is an integer number (33314286).

Almost surely, 2^66628571 is an apocalyptic number.

66628571 is a deficient number, since it is larger than the sum of its proper divisors (1).

66628571 is an equidigital number, since it uses as much as digits as its factorization.

66628571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 41.

The square root of 66628571 is about 8162.6326022920. The cubic root of 66628571 is about 405.4028831420.

The spelling of 66628571 in words is "sixty-six million, six hundred twenty-eight thousand, five hundred seventy-one".