20643628 has 12 divisors (see below), whose sum is σ = 36739080. Its totient is φ = 10146752.

The previous prime is 20643611. The next prime is 20643641. The reversal of 20643628 is 82634602.

It is a self number, because there is not a number n which added to its sum of digits gives 20643628.

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, 43501 + ... + 43972.

It is an arithmetic number, because the mean of its divisors is an integer number (3061590).

Almost surely, 2^20643628 is an apocalyptic number.

It is an amenable number.

20643628 is a deficient number, since it is larger than the sum of its proper divisors (16095452).

20643628 is a wasteful number, since it uses less digits than its factorization.

20643628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87536 (or 87534 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 20643628 is about 4543.5259435817. The cubic root of 20643628 is about 274.3228651832.

It can be divided in two parts, 206 and 43628, that added together give a palindrome (43834).

The spelling of 20643628 in words is "twenty million, six hundred forty-three thousand, six hundred twenty-eight".