20639228 has 24 divisors (see below), whose sum is σ = 36966384. Its totient is φ = 10080000.

The previous prime is 20639219. The next prime is 20639231. The reversal of 20639228 is 82293602.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20639194 and 20639203.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61076 + ... + 61412.

It is an arithmetic number, because the mean of its divisors is an integer number (1540266).

Almost surely, 2^20639228 is an apocalyptic number.

It is an amenable number.

20639228 is a deficient number, since it is larger than the sum of its proper divisors (16327156).

20639228 is a wasteful number, since it uses less digits than its factorization.

20639228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653 (or 651 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 20639228 is about 4543.0417123333. The cubic root of 20639228 is about 274.3033739973.

The spelling of 20639228 in words is "twenty million, six hundred thirty-nine thousand, two hundred twenty-eight".