20641564 has 24 divisors (see below), whose sum is σ = 36771840. Its totient is φ = 10137456.

The previous prime is 20641559. The next prime is 20641571. The reversal of 20641564 is 46514602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90819 + ... + 91045.

It is an arithmetic number, because the mean of its divisors is an integer number (1532160).

Almost surely, 2^20641564 is an apocalyptic number.

It is an amenable number.

20641564 is a deficient number, since it is larger than the sum of its proper divisors (16130276).

20641564 is a wasteful number, since it uses less digits than its factorization.

20641564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537 (or 535 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 20641564 is about 4543.2988015318. The cubic root of 20641564 is about 274.3137223900.

The spelling of 20641564 in words is "twenty million, six hundred forty-one thousand, five hundred sixty-four".