20690239 has 4 divisors (see below), whose sum is σ = 20756656. Its totient is φ = 20623824.

The previous prime is 20690231. The next prime is 20690251. The reversal of 20690239 is 93209602.

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 20690239 - 2³ = 20690231 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 20690239.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20690231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32739 + ... + 33364.

It is an arithmetic number, because the mean of its divisors is an integer number (5189164).

Almost surely, 2^20690239 is an apocalyptic number.

20690239 is a deficient number, since it is larger than the sum of its proper divisors (66417).

20690239 is an equidigital number, since it uses as much as digits as its factorization.

20690239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66416.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 20690239 is about 4548.6524378106. The cubic root of 20690239 is about 274.5291734228.

The spelling of 20690239 in words is "twenty million, six hundred ninety thousand, two hundred thirty-nine".