20839990 has 16 divisors (see below), whose sum is σ = 37878048. Its totient is φ = 8254656.

The previous prime is 20839969. The next prime is 20839997. The reversal of 20839990 is 9993802.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20839997) 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 7 ways as a sum of consecutive naturals, for example, 9087 + ... + 11146.

It is an arithmetic number, because the mean of its divisors is an integer number (2367378).

Almost surely, 2^20839990 is an apocalyptic number.

20839990 is a deficient number, since it is larger than the sum of its proper divisors (17038058).

20839990 is a wasteful number, since it uses less digits than its factorization.

20839990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20343.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 20839990 is about 4565.0837889353. The cubic root of 20839990 is about 275.1899073925.

The spelling of 20839990 in words is "twenty million, eight hundred thirty-nine thousand, nine hundred ninety".