66720569 has 4 divisors (see below), whose sum is σ = 66986640. Its totient is φ = 66454500.

The previous prime is 66720559. The next prime is 66720659. The reversal of 66720569 is 96502766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66720569 - 2⁴ = 66720553 is a prime.

It is a super-2 number, since 2×66720569² = 8903268655367522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66720559) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132659 + ... + 133160.

It is an arithmetic number, because the mean of its divisors is an integer number (16746660).

Almost surely, 2^66720569 is an apocalyptic number.

It is an amenable number.

66720569 is a deficient number, since it is larger than the sum of its proper divisors (266071).

66720569 is a wasteful number, since it uses less digits than its factorization.

66720569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266070.

The product of its (nonzero) digits is 136080, while the sum is 41.

The square root of 66720569 is about 8168.2659726529. The cubic root of 66720569 is about 405.5893852252.

The spelling of 66720569 in words is "sixty-six million, seven hundred twenty thousand, five hundred sixty-nine".