1664423655606 has 128 divisors (see below), whose sum is σ = 3797818444800. Its totient is φ = 540148227840.

The previous prime is 1664423655593. The next prime is 1664423655617. The reversal of 1664423655606 is 6065563244661.

1664423655606 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 4 + 23 + 6 + 5 + 5 + 606 = 666.

It is a super-2 number, since 2×1664423655606² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 156557911 + ... + 156568541.

It is an arithmetic number, because the mean of its divisors is an integer number (29670456600).

Almost surely, 2^{1664423655606} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1664423655606, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1898909222400).

1664423655606 is an abundant number, since it is smaller than the sum of its proper divisors (2133394789194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1664423655606 is a wasteful number, since it uses less digits than its factorization.

1664423655606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11171 (or 11165 counting only the distinct ones).

The product of its (nonzero) digits is 18662400, while the sum is 54.

The spelling of 1664423655606 in words is "one trillion, six hundred sixty-four billion, four hundred twenty-three million, six hundred fifty-five thousand, six hundred six".