20905745 has 8 divisors (see below), whose sum is σ = 28670784. Its totient is φ = 14335344.

The previous prime is 20905727. The next prime is 20905747. The reversal of 20905745 is 54750902.

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-20905745 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20905747) 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, 298619 + ... + 298688.

It is an arithmetic number, because the mean of its divisors is an integer number (3583848).

Almost surely, 2^20905745 is an apocalyptic number.

It is an amenable number.

20905745 is a deficient number, since it is larger than the sum of its proper divisors (7765039).

20905745 is an equidigital number, since it uses as much as digits as its factorization.

20905745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597319.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 20905745 is about 4572.2800657877. The cubic root of 20905745 is about 275.4790328388.

The spelling of 20905745 in words is "twenty million, nine hundred five thousand, seven hundred forty-five".