20647643 has 8 divisors (see below), whose sum is σ = 21427200. Its totient is φ = 19875240.

The previous prime is 20647631. The next prime is 20647651. The reversal of 20647643 is 34674602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20647643 - 2⁶ = 20647579 is a prime.

It is a super-2 number, since 2×20647643² = 852650322910898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20647663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4496 + ... + 7842.

It is an arithmetic number, because the mean of its divisors is an integer number (2678400).

Almost surely, 2^20647643 is an apocalyptic number.

20647643 is a deficient number, since it is larger than the sum of its proper divisors (779557).

20647643 is a wasteful number, since it uses less digits than its factorization.

20647643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3577.

The product of its (nonzero) digits is 24192, while the sum is 32.

The square root of 20647643 is about 4543.9677595687. The cubic root of 20647643 is about 274.3406484738.

The spelling of 20647643 in words is "twenty million, six hundred forty-seven thousand, six hundred forty-three".