20217739 has 4 divisors (see below), whose sum is σ = 20232856. Its totient is φ = 20202624.

The previous prime is 20217733. The next prime is 20217749. The reversal of 20217739 is 93771202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20217739 - 2¹³ = 20209547 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20217739.

It is not an unprimeable number, because it can be changed into a prime (20217733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5334 + ... + 8299.

It is an arithmetic number, because the mean of its divisors is an integer number (5058214).

Almost surely, 2^20217739 is an apocalyptic number.

20217739 is a deficient number, since it is larger than the sum of its proper divisors (15117).

20217739 is a wasteful number, since it uses less digits than its factorization.

20217739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15116.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 20217739 is about 4496.4140156351. The cubic root of 20217739 is about 272.4232659963.

The spelling of 20217739 in words is "twenty million, two hundred seventeen thousand, seven hundred thirty-nine".