66164639 has 4 divisors (see below), whose sum is σ = 66220224. Its totient is φ = 66109056.

The previous prime is 66164591. The next prime is 66164641. The reversal of 66164639 is 93646166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66164639 - 2⁸ = 66164383 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66164596 and 66164605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66164699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25967 + ... + 28400.

It is an arithmetic number, because the mean of its divisors is an integer number (16555056).

Almost surely, 2^66164639 is an apocalyptic number.

66164639 is a deficient number, since it is larger than the sum of its proper divisors (55585).

66164639 is a wasteful number, since it uses less digits than its factorization.

66164639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55584.

The product of its digits is 139968, while the sum is 41.

The square root of 66164639 is about 8134.1649233342. The cubic root of 66164639 is about 404.4597562236.

The spelling of 66164639 in words is "sixty-six million, one hundred sixty-four thousand, six hundred thirty-nine".