20643754 has 4 divisors (see below), whose sum is σ = 30965634. Its totient is φ = 10321876.

The previous prime is 20643739. The next prime is 20643757. The reversal of 20643754 is 45734602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20115225 + 528529 = 4485^2 + 727^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20643757) 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 as a sum of consecutive naturals, namely, 5160937 + ... + 5160940.

Almost surely, 2^20643754 is an apocalyptic number.

20643754 is a deficient number, since it is larger than the sum of its proper divisors (10321880).

20643754 is a wasteful number, since it uses less digits than its factorization.

20643754 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10321879.

The product of its (nonzero) digits is 20160, while the sum is 31.

The square root of 20643754 is about 4543.5398094437. The cubic root of 20643754 is about 274.3234232991.

The spelling of 20643754 in words is "twenty million, six hundred forty-three thousand, seven hundred fifty-four".