20494643 has 4 divisors (see below), whose sum is σ = 22071168. Its totient is φ = 18918120.

The previous prime is 20494603. The next prime is 20494651. The reversal of 20494643 is 34649402.

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

It is a de Polignac number, because none of the positive numbers 2^k-20494643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20494603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 788243 + ... + 788268.

It is an arithmetic number, because the mean of its divisors is an integer number (5517792).

Almost surely, 2^20494643 is an apocalyptic number.

20494643 is a deficient number, since it is larger than the sum of its proper divisors (1576525).

20494643 is a wasteful number, since it uses less digits than its factorization.

20494643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1576524.

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 20494643 is about 4527.1009487309. The cubic root of 20494643 is about 273.6613421260.

The spelling of 20494643 in words is "twenty million, four hundred ninety-four thousand, six hundred forty-three".