66072661 has 2 divisors, whose sum is σ = 66072662. Its totient is φ = 66072660.

The previous prime is 66072649. The next prime is 66072697. The reversal of 66072661 is 16627066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44635761 + 21436900 = 6681^2 + 4630^2 .

It is a cyclic number.

It is not a de Polignac number, because 66072661 - 2¹⁵ = 66039893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66075661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33036330 + 33036331.

It is an arithmetic number, because the mean of its divisors is an integer number (33036331).

Almost surely, 2^66072661 is an apocalyptic number.

It is an amenable number.

66072661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66072661 is an equidigital number, since it uses as much as digits as its factorization.

66072661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 66072661 is about 8128.5091498995. The cubic root of 66072661 is about 404.2722509755.

The spelling of 66072661 in words is "sixty-six million, seventy-two thousand, six hundred sixty-one".