20509929 has 24 divisors (see below), whose sum is σ = 33520032. Its totient is φ = 12428640.

The previous prime is 20509921. The next prime is 20509933. The reversal of 20509929 is 92990502.

It is not a de Polignac number, because 20509929 - 2³ = 20509921 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20509893 and 20509902.

It is not an unprimeable number, because it can be changed into a prime (20509921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1164 + ... + 6509.

It is an arithmetic number, because the mean of its divisors is an integer number (1396668).

Almost surely, 2^20509929 is an apocalyptic number.

It is an amenable number.

20509929 is a deficient number, since it is larger than the sum of its proper divisors (13010103).

20509929 is an equidigital number, since it uses as much as digits as its factorization.

20509929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7699 (or 7687 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 20509929 is about 4528.7889109562. The cubic root of 20509929 is about 273.7293623023.

The spelling of 20509929 in words is "twenty million, five hundred nine thousand, nine hundred twenty-nine".