21231219 has 16 divisors (see below), whose sum is σ = 29423520. Its totient is φ = 13601280.

The previous prime is 21231173. The next prime is 21231241. The reversal of 21231219 is 91213212.

It is not a de Polignac number, because 21231219 - 2⁹ = 21230707 is a prime.

It is a super-2 number, since 2×21231219² = 901529320451922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21231195 and 21231204.

It is not an unprimeable number, because it can be changed into a prime (21231269) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23659 + ... + 24539.

It is an arithmetic number, because the mean of its divisors is an integer number (1838970).

Almost surely, 2^21231219 is an apocalyptic number.

21231219 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21231219 is a deficient number, since it is larger than the sum of its proper divisors (8192301).

21231219 is a wasteful number, since it uses less digits than its factorization.

21231219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1190.

The product of its digits is 216, while the sum is 21.

The square root of 21231219 is about 4607.7346928833. The cubic root of 21231219 is about 276.9012885338.

The spelling of 21231219 in words is "twenty-one million, two hundred thirty-one thousand, two hundred nineteen".