66238661 has 4 divisors (see below), whose sum is σ = 68375424. Its totient is φ = 64101900.

The previous prime is 66238637. The next prime is 66238673. The reversal of 66238661 is 16683266.

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 a de Polignac number, because none of the positive numbers 2^k-66238661 is a prime.

It is a super-2 number, since 2×66238661² = 8775120422145842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66238631) 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, 1068335 + ... + 1068396.

It is an arithmetic number, because the mean of its divisors is an integer number (17093856).

Almost surely, 2^66238661 is an apocalyptic number.

It is an amenable number.

66238661 is a deficient number, since it is larger than the sum of its proper divisors (2136763).

66238661 is a wasteful number, since it uses less digits than its factorization.

66238661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2136762.

The product of its digits is 62208, while the sum is 38.

The square root of 66238661 is about 8138.7137190099. The cubic root of 66238661 is about 404.6105304271.

The spelling of 66238661 in words is "sixty-six million, two hundred thirty-eight thousand, six hundred sixty-one".