66491601 has 8 divisors (see below), whose sum is σ = 96715104. Its totient is φ = 40297920.

The previous prime is 66491599. The next prime is 66491609. The reversal of 66491601 is 10619466.

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

It is not a de Polignac number, because 66491601 - 2¹ = 66491599 is a prime.

It is a super-2 number, since 2×66491601² = 8842266007086402, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 2014897 = 66491601 / (6 + 6 + 4 + 9 + 1 + 6 + 0 + 1).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66491609) 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, 1007416 + ... + 1007481.

It is an arithmetic number, because the mean of its divisors is an integer number (12089388).

Almost surely, 2^66491601 is an apocalyptic number.

It is an amenable number.

66491601 is a deficient number, since it is larger than the sum of its proper divisors (30223503).

66491601 is a wasteful number, since it uses less digits than its factorization.

66491601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014911.

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 66491601 is about 8154.2382231573. The cubic root of 66491601 is about 405.1248936564.

The spelling of 66491601 in words is "sixty-six million, four hundred ninety-one thousand, six hundred one".