20643436 has 12 divisors (see below), whose sum is σ = 39410280. Its totient is φ = 9383360.

The previous prime is 20643431. The next prime is 20643439. The reversal of 20643436 is 63434602.

It is not an unprimeable number, because it can be changed into a prime (20643431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 234541 + ... + 234628.

It is an arithmetic number, because the mean of its divisors is an integer number (3284190).

Almost surely, 2^20643436 is an apocalyptic number.

It is an amenable number.

20643436 is a deficient number, since it is larger than the sum of its proper divisors (18766844).

20643436 is a wasteful number, since it uses less digits than its factorization.

20643436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469184 (or 469182 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 28.

The square root of 20643436 is about 4543.5048145677. The cubic root of 20643436 is about 274.3220147165.

The spelling of 20643436 in words is "twenty million, six hundred forty-three thousand, four hundred thirty-six".