20605645644 has 12 divisors (see below), whose sum is σ = 48079839864. Its totient is φ = 6868548544.

The previous prime is 20605645639. The next prime is 20605645649. The reversal of 20605645644 is 44654650602.

It is an interprime number because it is at equal distance from previous prime (20605645639) and next prime (20605645649).

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 = 20605645596 and 20605645605.

It is not an unprimeable number, because it can be changed into a prime (20605645649) 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, 858568557 + ... + 858568580.

It is an arithmetic number, because the mean of its divisors is an integer number (4006653322).

Almost surely, 2^20605645644 is an apocalyptic number.

It is an amenable number.

20605645644 is an abundant number, since it is smaller than the sum of its proper divisors (27474194220).

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

20605645644 is a wasteful number, since it uses less digits than its factorization.

20605645644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1717137144 (or 1717137142 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 42.

The spelling of 20605645644 in words is "twenty billion, six hundred five million, six hundred forty-five thousand, six hundred forty-four".