20643629 has 4 divisors (see below), whose sum is σ = 20653920. Its totient is φ = 20633340.

The previous prime is 20643611. The next prime is 20643641. The reversal of 20643629 is 92634602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20643629 - 2¹⁶ = 20578093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20643595 and 20643604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643229) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1049 + ... + 6510.

It is an arithmetic number, because the mean of its divisors is an integer number (5163480).

Almost surely, 2^20643629 is an apocalyptic number.

It is an amenable number.

20643629 is a deficient number, since it is larger than the sum of its proper divisors (10291).

20643629 is an equidigital number, since it uses as much as digits as its factorization.

20643629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10290.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 20643629 is about 4543.5260536284. The cubic root of 20643629 is about 274.3228696127.

The spelling of 20643629 in words is "twenty million, six hundred forty-three thousand, six hundred twenty-nine".