20145421 has 2 divisors, whose sum is σ = 20145422. Its totient is φ = 20145420.

The previous prime is 20145407. The next prime is 20145449. The reversal of 20145421 is 12454102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18966025 + 1179396 = 4355^2 + 1086^2 .

It is a cyclic number.

It is not a de Polignac number, because 20145421 - 2¹⁷ = 20014349 is a prime.

It is a super-3 number, since 3×20145421³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20145721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10072710 + 10072711.

It is an arithmetic number, because the mean of its divisors is an integer number (10072711).

Almost surely, 2^20145421 is an apocalyptic number.

It is an amenable number.

20145421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20145421 is an equidigital number, since it uses as much as digits as its factorization.

20145421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 20145421 is about 4488.3650698222. The cubic root of 20145421 is about 272.0980624288.

Adding to 20145421 its reverse (12454102), we get a palindrome (32599523).

The spelling of 20145421 in words is "twenty million, one hundred forty-five thousand, four hundred twenty-one".