20493643 has 4 divisors (see below), whose sum is σ = 20503000. Its totient is φ = 20484288.

The previous prime is 20493637. The next prime is 20493659. The reversal of 20493643 is 34639402.

It is a semiprime because it is the product of two primes, 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 20493643 - 2⁹ = 20493131 is a prime.

It is a super-2 number, since 2×20493643² = 839978806822898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20493043) 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, 571 + ... + 6427.

It is an arithmetic number, because the mean of its divisors is an integer number (5125750).

Almost surely, 2^20493643 is an apocalyptic number.

20493643 is a deficient number, since it is larger than the sum of its proper divisors (9357).

20493643 is an equidigital number, since it uses as much as digits as its factorization.

20493643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9356.

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 20493643 is about 4526.9905014259. The cubic root of 20493643 is about 273.6568911126.

The spelling of 20493643 in words is "twenty million, four hundred ninety-three thousand, six hundred forty-three".