421899409 has 2 divisors, whose sum is σ = 421899410. Its totient is φ = 421899408.

The previous prime is 421899347. The next prime is 421899449. The reversal of 421899409 is 904998124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351675009 + 70224400 = 18753^2 + 8380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421899409 is a prime.

It is a super-2 number, since 2×421899409² = 355998222629098562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (421899449) 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, 210949704 + 210949705.

It is an arithmetic number, because the mean of its divisors is an integer number (210949705).

Almost surely, 2^421899409 is an apocalyptic number.

It is an amenable number.

421899409 is a deficient number, since it is larger than the sum of its proper divisors (1).

421899409 is an equidigital number, since it uses as much as digits as its factorization.

421899409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 46.

The square root of 421899409 is about 20540.1900916228. The cubic root of 421899409 is about 750.0144643136.

The spelling of 421899409 in words is "four hundred twenty-one million, eight hundred ninety-nine thousand, four hundred nine".