20712643 has 6 divisors (see below), whose sum is σ = 24094356. Its totient is φ = 17753652.

The previous prime is 20712631. The next prime is 20712649. The reversal of 20712643 is 34621702.

It is not a de Polignac number, because 20712643 - 2¹⁷ = 20581571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20712649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 211305 + ... + 211402.

It is an arithmetic number, because the mean of its divisors is an integer number (4015726).

Almost surely, 2^20712643 is an apocalyptic number.

20712643 is a deficient number, since it is larger than the sum of its proper divisors (3381713).

20712643 is an equidigital number, since it uses as much as digits as its factorization.

20712643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422721 (or 422714 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 20712643 is about 4551.1144788942. The cubic root of 20712643 is about 274.6282271028.

The spelling of 20712643 in words is "twenty million, seven hundred twelve thousand, six hundred forty-three".