1566217644 has 12 divisors (see below), whose sum is σ = 3654507864. Its totient is φ = 522072544.

The previous prime is 1566217607. The next prime is 1566217649. The reversal of 1566217644 is 4467126651.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 1566217596 and 1566217605.

It is not an unprimeable number, because it can be changed into a prime (1566217649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65259057 + ... + 65259080.

It is an arithmetic number, because the mean of its divisors is an integer number (304542322).

Almost surely, 2^1566217644 is an apocalyptic number.

It is an amenable number.

1566217644 is an abundant number, since it is smaller than the sum of its proper divisors (2088290220).

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

1566217644 is a wasteful number, since it uses less digits than its factorization.

1566217644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130518144 (or 130518142 counting only the distinct ones).

The product of its digits is 241920, while the sum is 42.

The square root of 1566217644 is about 39575.4677041220. The cubic root of 1566217644 is about 1161.3167874661.

The spelling of 1566217644 in words is "one billion, five hundred sixty-six million, two hundred seventeen thousand, six hundred forty-four".