66189897 has 6 divisors (see below), whose sum is σ = 95607642. Its totient is φ = 44126592.

The previous prime is 66189889. The next prime is 66189911. The reversal of 66189897 is 79898166.

It can be written as a sum of positive squares in only one way, i.e., 47734281 + 18455616 = 6909^2 + 4296^2 .

It is not a de Polignac number, because 66189897 - 2³ = 66189889 is a prime.

It is a super-2 number, since 2×66189897² = 8762204929741218, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66189817) 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, 3677208 + ... + 3677225.

It is an arithmetic number, because the mean of its divisors is an integer number (15934607).

Almost surely, 2^66189897 is an apocalyptic number.

It is an amenable number.

66189897 is a deficient number, since it is larger than the sum of its proper divisors (29417745).

66189897 is a wasteful number, since it uses less digits than its factorization.

66189897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7354439 (or 7354436 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 66189897 is about 8135.7173623473. The cubic root of 66189897 is about 404.5112164648.

The spelling of 66189897 in words is "sixty-six million, one hundred eighty-nine thousand, eight hundred ninety-seven".