20169421 has 2 divisors, whose sum is σ = 20169422. Its totient is φ = 20169420.

The previous prime is 20169419. The next prime is 20169427. The reversal of 20169421 is 12496102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13793796 + 6375625 = 3714^2 + 2525^2 .

It is a cyclic number.

It is not a de Polignac number, because 20169421 - 2¹ = 20169419 is a prime.

Together with 20169419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20169427) 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, 10084710 + 10084711.

It is an arithmetic number, because the mean of its divisors is an integer number (10084711).

Almost surely, 2^20169421 is an apocalyptic number.

It is an amenable number.

20169421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20169421 is an equidigital number, since it uses as much as digits as its factorization.

20169421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 20169421 is about 4491.0378533252. The cubic root of 20169421 is about 272.2060731099.

The spelling of 20169421 in words is "twenty million, one hundred sixty-nine thousand, four hundred twenty-one".