20705129 has 8 divisors (see below), whose sum is σ = 21688512. Its totient is φ = 19728720.

The previous prime is 20705119. The next prime is 20705131. The reversal of 20705129 is 92150702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20705129 - 2¹² = 20701033 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20705098 and 20705107.

It is not an unprimeable number, because it can be changed into a prime (20705119) 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, 4919 + ... + 8099.

It is an arithmetic number, because the mean of its divisors is an integer number (2711064).

Almost surely, 2^20705129 is an apocalyptic number.

It is an amenable number.

20705129 is a deficient number, since it is larger than the sum of its proper divisors (983383).

20705129 is a wasteful number, since it uses less digits than its factorization.

20705129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3487.

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 20705129 is about 4550.2888919276. The cubic root of 20705129 is about 274.5950137962.

The spelling of 20705129 in words is "twenty million, seven hundred five thousand, one hundred twenty-nine".