20021656 has 16 divisors (see below), whose sum is σ = 37591200. Its totient is φ = 9997344.

The previous prime is 20021641. The next prime is 20021663. The reversal of 20021656 is 65612002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7690 + ... + 9958.

It is an arithmetic number, because the mean of its divisors is an integer number (2349450).

Almost surely, 2^20021656 is an apocalyptic number.

It is an amenable number.

20021656 is a deficient number, since it is larger than the sum of its proper divisors (17569544).

20021656 is a wasteful number, since it uses less digits than its factorization.

20021656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3378 (or 3374 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20021656 is about 4474.5565143375. The cubic root of 20021656 is about 271.5396986991.

Adding to 20021656 its reverse (65612002), we get a palindrome (85633658).

The spelling of 20021656 in words is "twenty million, twenty-one thousand, six hundred fifty-six".