20656429 has 2 divisors, whose sum is σ = 20656430. Its totient is φ = 20656428.

The previous prime is 20656409. The next prime is 20656451. The reversal of 20656429 is 92465602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17867529 + 2788900 = 4227^2 + 1670^2 .

It is a cyclic number.

It is not a de Polignac number, because 20656429 - 2¹³ = 20648237 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20656394 and 20656403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20656409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328214 + 10328215.

It is an arithmetic number, because the mean of its divisors is an integer number (10328215).

Almost surely, 2^20656429 is an apocalyptic number.

It is an amenable number.

20656429 is a deficient number, since it is larger than the sum of its proper divisors (1).

20656429 is an equidigital number, since it uses as much as digits as its factorization.

20656429 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 20656429 is about 4544.9344329704. The cubic root of 20656429 is about 274.3795554995.

The spelling of 20656429 in words is "twenty million, six hundred fifty-six thousand, four hundred twenty-nine".