20820929 has 2 divisors, whose sum is σ = 20820930. Its totient is φ = 20820928.

The previous prime is 20820889. The next prime is 20820959. The reversal of 20820929 is 92902802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18105025 + 2715904 = 4255^2 + 1648^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20820929 is a prime.

It is a super-2 number, since 2×20820929² = 867022168846082, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20820895 and 20820904.

It is not a weakly prime, because it can be changed into another prime (20820959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10410464 + 10410465.

It is an arithmetic number, because the mean of its divisors is an integer number (10410465).

Almost surely, 2^20820929 is an apocalyptic number.

It is an amenable number.

20820929 is a deficient number, since it is larger than the sum of its proper divisors (1).

20820929 is an equidigital number, since it uses as much as digits as its factorization.

20820929 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 20820929 is about 4562.9956169166. The cubic root of 20820929 is about 275.1059822907.

The spelling of 20820929 in words is "twenty million, eight hundred twenty thousand, nine hundred twenty-nine".