20995656 has 64 divisors (see below), whose sum is σ = 58164480. Its totient is φ = 6262080.

The previous prime is 20995633. The next prime is 20995657. The reversal of 20995656 is 65659902.

It is not an unprimeable number, because it can be changed into a prime (20995657) 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, 17095 + ... + 18281.

It is an arithmetic number, because the mean of its divisors is an integer number (908820).

Almost surely, 2^20995656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20995656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29082240).

20995656 is an abundant number, since it is smaller than the sum of its proper divisors (37168824).

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

20995656 is a wasteful number, since it uses less digits than its factorization.

20995656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1274 (or 1270 counting only the distinct ones).

The product of its (nonzero) digits is 145800, while the sum is 42.

The square root of 20995656 is about 4582.1017011847. The cubic root of 20995656 is about 275.8733928872.

It can be divided in two parts, 209956 and 56, that added together give a palindrome (210012).

The spelling of 20995656 in words is "twenty million, nine hundred ninety-five thousand, six hundred fifty-six".