421569917 has 2 divisors, whose sum is σ = 421569918. Its totient is φ = 421569916.

The previous prime is 421569851. The next prime is 421569919. The reversal of 421569917 is 719965124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 414285316 + 7284601 = 20354^2 + 2699^2 .

It is a cyclic number.

It is not a de Polignac number, because 421569917 - 2¹⁰ = 421568893 is a prime.

Together with 421569919, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421569919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210784958 + 210784959.

It is an arithmetic number, because the mean of its divisors is an integer number (210784959).

Almost surely, 2^421569917 is an apocalyptic number.

It is an amenable number.

421569917 is a deficient number, since it is larger than the sum of its proper divisors (1).

421569917 is an equidigital number, since it uses as much as digits as its factorization.

421569917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 44.

The square root of 421569917 is about 20532.1678592398. The cubic root of 421569917 is about 749.8191664766.

The spelling of 421569917 in words is "four hundred twenty-one million, five hundred sixty-nine thousand, nine hundred seventeen".