20661696 has 112 divisors (see below), whose sum is σ = 66324480. Its totient is φ = 6255360.

The previous prime is 20661691. The next prime is 20661703. The reversal of 20661696 is 69616602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20661696.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18465 + ... + 19551.

Almost surely, 2^20661696 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 20661696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33162240).

20661696 is an abundant number, since it is smaller than the sum of its proper divisors (45662784).

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

20661696 is a wasteful number, since it uses less digits than its factorization.

20661696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119 (or 1103 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 20661696 is about 4545.5138323406. The cubic root of 20661696 is about 274.4028740558.

The spelling of 20661696 in words is "twenty million, six hundred sixty-one thousand, six hundred ninety-six".