20872429 has 2 divisors, whose sum is σ = 20872430. Its totient is φ = 20872428.

The previous prime is 20872427. The next prime is 20872433. The reversal of 20872429 is 92427802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20385225 + 487204 = 4515^2 + 698^2 .

It is a cyclic number.

It is not a de Polignac number, because 20872429 - 2¹ = 20872427 is a prime.

Together with 20872427, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 20872394 and 20872403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20872421) 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 as a sum of consecutive naturals, namely, 10436214 + 10436215.

It is an arithmetic number, because the mean of its divisors is an integer number (10436215).

Almost surely, 2^20872429 is an apocalyptic number.

It is an amenable number.

20872429 is a deficient number, since it is larger than the sum of its proper divisors (1).

20872429 is an equidigital number, since it uses as much as digits as its factorization.

20872429 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20872429 is about 4568.6353542387. The cubic root of 20872429 is about 275.3326179156.

The spelling of 20872429 in words is "twenty million, eight hundred seventy-two thousand, four hundred twenty-nine".