20129939 has 4 divisors (see below), whose sum is σ = 20460000. Its totient is φ = 19799880.

The previous prime is 20129929. The next prime is 20129951. The reversal of 20129939 is 93992102.

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 20129939 - 2¹² = 20125843 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20129899 and 20129908.

It is not an unprimeable number, because it can be changed into a prime (20129909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164939 + ... + 165060.

It is an arithmetic number, because the mean of its divisors is an integer number (5115000).

Almost surely, 2^20129939 is an apocalyptic number.

20129939 is a deficient number, since it is larger than the sum of its proper divisors (330061).

20129939 is an equidigital number, since it uses as much as digits as its factorization.

20129939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330060.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 20129939 is about 4486.6400568800. The cubic root of 20129939 is about 272.0283410132.

The spelling of 20129939 in words is "twenty million, one hundred twenty-nine thousand, nine hundred thirty-nine".