66725561 has 8 divisors (see below), whose sum is σ = 80743680. Its totient is φ = 53828928.

The previous prime is 66725539. The next prime is 66725567. The reversal of 66725561 is 16552766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66725561 - 2⁶ = 66725497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66725567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 280241 + ... + 280478.

It is an arithmetic number, because the mean of its divisors is an integer number (10092960).

Almost surely, 2^66725561 is an apocalyptic number.

It is an amenable number.

66725561 is a deficient number, since it is larger than the sum of its proper divisors (14018119).

66725561 is a wasteful number, since it uses less digits than its factorization.

66725561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560743.

The product of its digits is 75600, while the sum is 38.

The square root of 66725561 is about 8168.5715397492. The cubic root of 66725561 is about 405.5995003054.

The spelling of 66725561 in words is "sixty-six million, seven hundred twenty-five thousand, five hundred sixty-one".