66491789 has 8 divisors (see below), whose sum is σ = 81836160. Its totient is φ = 52608816.

The previous prime is 66491783. The next prime is 66491819. The reversal of 66491789 is 98719466.

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

It is not a de Polignac number, because 66491789 - 2¹² = 66487693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66491783) 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, 365249 + ... + 365430.

It is an arithmetic number, because the mean of its divisors is an integer number (10229520).

Almost surely, 2^66491789 is an apocalyptic number.

It is an amenable number.

66491789 is a deficient number, since it is larger than the sum of its proper divisors (15344371).

66491789 is a wasteful number, since it uses less digits than its factorization.

66491789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730699.

The product of its digits is 653184, while the sum is 50.

The square root of 66491789 is about 8154.2497508968. The cubic root of 66491789 is about 405.1252754761.

The spelling of 66491789 in words is "sixty-six million, four hundred ninety-one thousand, seven hundred eighty-nine".