66728737 has 2 divisors, whose sum is σ = 66728738. Its totient is φ = 66728736.

The previous prime is 66728707. The next prime is 66728807. The reversal of 66728737 is 73782766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66650896 + 77841 = 8164^2 + 279^2 .

It is a cyclic number.

It is not a de Polignac number, because 66728737 - 2⁷ = 66728609 is a prime.

It is not a weakly prime, because it can be changed into another prime (66728707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33364368 + 33364369.

It is an arithmetic number, because the mean of its divisors is an integer number (33364369).

Almost surely, 2^66728737 is an apocalyptic number.

It is an amenable number.

66728737 is a deficient number, since it is larger than the sum of its proper divisors (1).

66728737 is an equidigital number, since it uses as much as digits as its factorization.

66728737 is an evil number, because the sum of its binary digits is even.

The product of its digits is 592704, while the sum is 46.

The square root of 66728737 is about 8168.7659410709. The cubic root of 66728737 is about 405.6059354384.

The spelling of 66728737 in words is "sixty-six million, seven hundred twenty-eight thousand, seven hundred thirty-seven".