66649397 has 8 divisors (see below), whose sum is σ = 70552800. Its totient is φ = 62785584.

The previous prime is 66649381. The next prime is 66649399. The reversal of 66649397 is 79394666.

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 66649397 - 2⁴ = 66649381 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 (66649399) 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, 6398 + ... + 13199.

It is an arithmetic number, because the mean of its divisors is an integer number (8819100).

Almost surely, 2^66649397 is an apocalyptic number.

It is an amenable number.

66649397 is a deficient number, since it is larger than the sum of its proper divisors (3903403).

66649397 is a wasteful number, since it uses less digits than its factorization.

66649397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19795.

The product of its digits is 1469664, while the sum is 50.

The square root of 66649397 is about 8163.9081939963. The cubic root of 66649397 is about 405.4451174808.

It can be divided in two parts, 6664 and 9397, that added together give a palindrome (16061).

The spelling of 66649397 in words is "sixty-six million, six hundred forty-nine thousand, three hundred ninety-seven".