21522219 has 4 divisors (see below), whose sum is σ = 28696296. Its totient is φ = 14348144.

The previous prime is 21522217. The next prime is 21522223. The reversal of 21522219 is 91222512.

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 21522219 - 2¹ = 21522217 is a prime.

It is a super-2 number, since 2×21522219² = 926411821367922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21522217) 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, 3587034 + ... + 3587039.

It is an arithmetic number, because the mean of its divisors is an integer number (7174074).

Almost surely, 2^21522219 is an apocalyptic number.

21522219 is a deficient number, since it is larger than the sum of its proper divisors (7174077).

21522219 is an equidigital number, since it uses as much as digits as its factorization.

21522219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7174076.

The product of its digits is 720, while the sum is 24.

The square root of 21522219 is about 4639.2045654401. The cubic root of 21522219 is about 278.1606433131.

It can be divided in two parts, 2152 and 2219, that added together give a triangular number (4371 = T₉₃).

The spelling of 21522219 in words is "twenty-one million, five hundred twenty-two thousand, two hundred nineteen".