20666224 has 40 divisors (see below), whose sum is σ = 42514640. Its totient is φ = 9704448.

The previous prime is 20666221. The next prime is 20666249. The reversal of 20666224 is 42266602.

It is a junction number, because it is equal to n+sod(n) for n = 20666192 and 20666201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20666221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47512 + ... + 47944.

It is an arithmetic number, because the mean of its divisors is an integer number (1062866).

Almost surely, 2^20666224 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 20666224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21257320).

20666224 is an abundant number, since it is smaller than the sum of its proper divisors (21848416).

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

20666224 is a wasteful number, since it uses less digits than its factorization.

20666224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617 (or 611 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 20666224 is about 4546.0118785591. The cubic root of 20666224 is about 274.4229176744.

It can be divided in two parts, 206 and 66224, that added together give a triangular number (66430 = T₃₆₄).

The spelling of 20666224 in words is "twenty million, six hundred sixty-six thousand, two hundred twenty-four".