421003391 has 2 divisors, whose sum is σ = 421003392. Its totient is φ = 421003390.

The previous prime is 421003379. The next prime is 421003421. The reversal of 421003391 is 193300124.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421003391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (421003301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210501695 + 210501696.

It is an arithmetic number, because the mean of its divisors is an integer number (210501696).

Almost surely, 2^421003391 is an apocalyptic number.

421003391 is a deficient number, since it is larger than the sum of its proper divisors (1).

421003391 is an equidigital number, since it uses as much as digits as its factorization.

421003391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 421003391 is about 20518.3671621306. The cubic root of 421003391 is about 749.4831348453.

It can be divided in two parts, 4210033 and 91, that added together give a palindrome (4210124).

The spelling of 421003391 in words is "four hundred twenty-one million, three thousand, three hundred ninety-one".