66225661 has 4 divisors (see below), whose sum is σ = 66517632. Its totient is φ = 65933692.

The previous prime is 66225631. The next prime is 66225667. The reversal of 66225661 is 16652266.

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 66225661 - 2²¹ = 64128509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66225667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145645 + ... + 146098.

It is an arithmetic number, because the mean of its divisors is an integer number (16629408).

Almost surely, 2^66225661 is an apocalyptic number.

It is an amenable number.

66225661 is a deficient number, since it is larger than the sum of its proper divisors (291971).

66225661 is a wasteful number, since it uses less digits than its factorization.

66225661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291970.

The product of its digits is 25920, while the sum is 34.

The square root of 66225661 is about 8137.9150278189. The cubic root of 66225661 is about 404.5840590736.

The spelling of 66225661 in words is "sixty-six million, two hundred twenty-five thousand, six hundred sixty-one".