20564146643 has 16 divisors (see below), whose sum is σ = 20846280000. Its totient is φ = 20284463232.

The previous prime is 20564146619. The next prime is 20564146657. The reversal of 20564146643 is 34664146502.

It is a cyclic number.

It is not a de Polignac number, because 20564146643 - 2⁶ = 20564146579 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20564146643.

It is not an unprimeable number, because it can be changed into a prime (20564146663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24805553 + ... + 24806381.

It is an arithmetic number, because the mean of its divisors is an integer number (1302892500).

Almost surely, 2^20564146643 is an apocalyptic number.

20564146643 is a deficient number, since it is larger than the sum of its proper divisors (282133357).

20564146643 is a wasteful number, since it uses less digits than its factorization.

20564146643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1934.

The product of its (nonzero) digits is 414720, while the sum is 41.

The spelling of 20564146643 in words is "twenty billion, five hundred sixty-four million, one hundred forty-six thousand, six hundred forty-three".