21234091 has 2 divisors, whose sum is σ = 21234092. Its totient is φ = 21234090.

The previous prime is 21234067. The next prime is 21234097. The reversal of 21234091 is 19043212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21234091 - 2⁹ = 21233579 is a prime.

It is not a weakly prime, because it can be changed into another prime (21234097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617045 + 10617046.

It is an arithmetic number, because the mean of its divisors is an integer number (10617046).

Almost surely, 2^21234091 is an apocalyptic number.

21234091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234091 is an equidigital number, since it uses as much as digits as its factorization.

21234091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21234091 is about 4608.0463322323. The cubic root of 21234091 is about 276.9137736804.

The spelling of 21234091 in words is "twenty-one million, two hundred thirty-four thousand, ninety-one".