21121219 has 4 divisors (see below), whose sum is σ = 24138544. Its totient is φ = 18103896.

The previous prime is 21121211. The next prime is 21121223. The reversal of 21121219 is 91212112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21121219 - 2³ = 21121211 is a prime.

It is a super-2 number, since 2×21121219² = 892211784091922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121196 and 21121205.

It is not an unprimeable number, because it can be changed into a prime (21121211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1508652 + ... + 1508665.

It is an arithmetic number, because the mean of its divisors is an integer number (6034636).

Almost surely, 2^21121219 is an apocalyptic number.

21121219 is a deficient number, since it is larger than the sum of its proper divisors (3017325).

21121219 is an equidigital number, since it uses as much as digits as its factorization.

21121219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3017324.

The product of its digits is 72, while the sum is 19.

The square root of 21121219 is about 4595.7827407309. The cubic root of 21121219 is about 276.4222471574.

The spelling of 21121219 in words is "twenty-one million, one hundred twenty-one thousand, two hundred nineteen".