421020091 has 2 divisors, whose sum is σ = 421020092. Its totient is φ = 421020090.

The previous prime is 421020071. The next prime is 421020097. The reversal of 421020091 is 190020124.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 421020091 - 2⁵ = 421020059 is a prime.

It is not a weakly prime, because it can be changed into another prime (421020097) 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, 210510045 + 210510046.

It is an arithmetic number, because the mean of its divisors is an integer number (210510046).

Almost surely, 2^421020091 is an apocalyptic number.

421020091 is a deficient number, since it is larger than the sum of its proper divisors (1).

421020091 is an equidigital number, since it uses as much as digits as its factorization.

421020091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 421020091 is about 20518.7741105554. The cubic root of 421020091 is about 749.4930446649.

The spelling of 421020091 in words is "four hundred twenty-one million, twenty thousand, ninety-one".