664066406 has 4 divisors (see below), whose sum is σ = 996099612. Its totient is φ = 332033202.

The previous prime is 664066369. The next prime is 664066409. The reversal of 664066406 is 604660466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 604660466 = 2 ⋅302330233.

It is a self number, because there is not a number n which added to its sum of digits gives 664066406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664066409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166016600 + ... + 166016603.

It is an arithmetic number, because the mean of its divisors is an integer number (249024903).

Almost surely, 2^664066406 is an apocalyptic number.

664066406 is a deficient number, since it is larger than the sum of its proper divisors (332033206).

664066406 is a wasteful number, since it uses less digits than its factorization.

664066406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332033205.

The product of its (nonzero) digits is 124416, while the sum is 38.

The square root of 664066406 is about 25769.4859475310. The cubic root of 664066406 is about 872.4432164204.

The spelling of 664066406 in words is "six hundred sixty-four million, sixty-six thousand, four hundred six".