18820429 has 2 divisors, whose sum is σ = 18820430. Its totient is φ = 18820428.

The previous prime is 18820427. The next prime is 18820433. The reversal of 18820429 is 92402881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14402025 + 4418404 = 3795^2 + 2102^2 .

It is an emirp because it is prime and its reverse (92402881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18820429 - 2¹ = 18820427 is a prime.

Together with 18820427, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18820394 and 18820403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18820421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9410214 + 9410215.

It is an arithmetic number, because the mean of its divisors is an integer number (9410215).

Almost surely, 2^18820429 is an apocalyptic number.

It is an amenable number.

18820429 is a deficient number, since it is larger than the sum of its proper divisors (1).

18820429 is an equidigital number, since it uses as much as digits as its factorization.

18820429 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 18820429 is about 4338.2518368578. The cubic root of 18820429 is about 265.9968577087.

The spelling of 18820429 in words is "eighteen million, eight hundred twenty thousand, four hundred twenty-nine".