21919459 has 2 divisors, whose sum is σ = 21919460. Its totient is φ = 21919458.

The previous prime is 21919441. The next prime is 21919481. The reversal of 21919459 is 95491912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21919459 - 2⁵ = 21919427 is a prime.

It is not a weakly prime, because it can be changed into another prime (21919439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10959729 + 10959730.

It is an arithmetic number, because the mean of its divisors is an integer number (10959730).

Almost surely, 2^21919459 is an apocalyptic number.

21919459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21919459 is an equidigital number, since it uses as much as digits as its factorization.

21919459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 40.

The square root of 21919459 is about 4681.8221879948. The cubic root of 21919459 is about 279.8615769875.

The spelling of 21919459 in words is "twenty-one million, nine hundred nineteen thousand, four hundred fifty-nine".