66689901 has 6 divisors (see below), whose sum is σ = 96329870. Its totient is φ = 44459928.

The previous prime is 66689899. The next prime is 66689911. The reversal of 66689901 is 10998666.

It can be written as a sum of positive squares in only one way, i.e., 65124900 + 1565001 = 8070^2 + 1251^2 .

It is not a de Polignac number, because 66689901 - 2¹ = 66689899 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 (66689911) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3704986 + ... + 3705003.

Almost surely, 2^66689901 is an apocalyptic number.

It is an amenable number.

66689901 is a deficient number, since it is larger than the sum of its proper divisors (29639969).

66689901 is a wasteful number, since it uses less digits than its factorization.

66689901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7409995 (or 7409992 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 66689901 is about 8166.3884918610. The cubic root of 66689901 is about 405.5272328698.

The spelling of 66689901 in words is "sixty-six million, six hundred eighty-nine thousand, nine hundred one".