20997219 has 4 divisors (see below), whose sum is σ = 27996296. Its totient is φ = 13998144.

The previous prime is 20997217. The next prime is 20997253. The reversal of 20997219 is 91279902.

It is a happy number.

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

It is not a de Polignac number, because 20997219 - 2¹ = 20997217 is a prime.

It is a super-2 number, since 2×20997219² = 881766411467922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20997211) 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, 3499534 + ... + 3499539.

It is an arithmetic number, because the mean of its divisors is an integer number (6999074).

Almost surely, 2^20997219 is an apocalyptic number.

20997219 is a deficient number, since it is larger than the sum of its proper divisors (6999077).

20997219 is an equidigital number, since it uses as much as digits as its factorization.

20997219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6999076.

The product of its (nonzero) digits is 20412, while the sum is 39.

The square root of 20997219 is about 4582.2722529330. The cubic root of 20997219 is about 275.8802384209.

The spelling of 20997219 in words is "twenty million, nine hundred ninety-seven thousand, two hundred nineteen".