20145643 has 8 divisors (see below), whose sum is σ = 24235520. Its totient is φ = 16358760.

The previous prime is 20145617. The next prime is 20145673. The reversal of 20145643 is 34654102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20145643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20145613) 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, 75603 + ... + 75868.

It is an arithmetic number, because the mean of its divisors is an integer number (3029440).

Almost surely, 2^20145643 is an apocalyptic number.

20145643 is a deficient number, since it is larger than the sum of its proper divisors (4089877).

20145643 is a wasteful number, since it uses less digits than its factorization.

20145643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151497.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20145643 is about 4488.3898003627. The cubic root of 20145643 is about 272.0990619206.

Adding to 20145643 its reverse (34654102), we get a palindrome (54799745).

The spelling of 20145643 in words is "twenty million, one hundred forty-five thousand, six hundred forty-three".