421421813 has 2 divisors, whose sum is σ = 421421814. Its totient is φ = 421421812.

The previous prime is 421421807. The next prime is 421421831. The reversal of 421421813 is 318124124.

Together with next prime (421421831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 360316324 + 61105489 = 18982^2 + 7817^2 .

It is a cyclic number.

It is not a de Polignac number, because 421421813 - 2¹⁶ = 421356277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421421213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210710906 + 210710907.

It is an arithmetic number, because the mean of its divisors is an integer number (210710907).

Almost surely, 2^421421813 is an apocalyptic number.

It is an amenable number.

421421813 is a deficient number, since it is larger than the sum of its proper divisors (1).

421421813 is an equidigital number, since it uses as much as digits as its factorization.

421421813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 26.

The square root of 421421813 is about 20528.5609091334. The cubic root of 421421813 is about 749.7313485207.

Adding to 421421813 its reverse (318124124), we get a palindrome (739545937).

The spelling of 421421813 in words is "four hundred twenty-one million, four hundred twenty-one thousand, eight hundred thirteen".