20613643 has 8 divisors (see below), whose sum is σ = 21012480. Its totient is φ = 20217960.

The previous prime is 20613601. The next prime is 20613647. The reversal of 20613643 is 34631602.

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

It is a de Polignac number, because none of the positive numbers 2^k-20613643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20613647) 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 7 ways as a sum of consecutive naturals, for example, 15478 + ... + 16756.

It is an arithmetic number, because the mean of its divisors is an integer number (2626560).

Almost surely, 2^20613643 is an apocalyptic number.

20613643 is a deficient number, since it is larger than the sum of its proper divisors (398837).

20613643 is a wasteful number, since it uses less digits than its factorization.

20613643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1577.

The product of its (nonzero) digits is 2592, while the sum is 25.

The square root of 20613643 is about 4540.2249944248. The cubic root of 20613643 is about 274.1899822601.

The spelling of 20613643 in words is "twenty million, six hundred thirteen thousand, six hundred forty-three".