421420243 has 2 divisors, whose sum is σ = 421420244. Its totient is φ = 421420242.

The previous prime is 421420217. The next prime is 421420267. The reversal of 421420243 is 342024124.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421420243 is a prime.

It is equal to p_22416025 and since 421420243 and 22416025 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (421420273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210710121 + 210710122.

It is an arithmetic number, because the mean of its divisors is an integer number (210710122).

Almost surely, 2^421420243 is an apocalyptic number.

421420243 is a deficient number, since it is larger than the sum of its proper divisors (1).

421420243 is an equidigital number, since it uses as much as digits as its factorization.

421420243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 22.

The square root of 421420243 is about 20528.5226696906. The cubic root of 421420243 is about 749.7304174823.

Adding to 421420243 its reverse (342024124), we get a palindrome (763444367).

The spelling of 421420243 in words is "four hundred twenty-one million, four hundred twenty thousand, two hundred forty-three".