20129717 has 6 divisors (see below), whose sum is σ = 21383778. Its totient is φ = 18945344.

The previous prime is 20129713. The next prime is 20129743. The reversal of 20129717 is 71792102.

It can be written as a sum of positive squares in 3 ways, for example, as 14205361 + 5924356 = 3769^2 + 2434^2 .

It is not a de Polignac number, because 20129717 - 2² = 20129713 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 20129717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20129713) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34538 + ... + 35115.

It is an arithmetic number, because the mean of its divisors is an integer number (3563963).

Almost surely, 2^20129717 is an apocalyptic number.

It is an amenable number.

20129717 is a deficient number, since it is larger than the sum of its proper divisors (1254061).

20129717 is an equidigital number, since it uses as much as digits as its factorization.

20129717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69687 (or 69670 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 20129717 is about 4486.6153166948. The cubic root of 20129717 is about 272.0273410016.

The spelling of 20129717 in words is "twenty million, one hundred twenty-nine thousand, seven hundred seventeen".