221211005 has 4 divisors (see below), whose sum is σ = 265453212. Its totient is φ = 176968800.

The previous prime is 221210993. The next prime is 221211017. The reversal of 221211005 is 500112122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 500112122 = 2 ⋅250056061.

It is an interprime number because it is at equal distance from previous prime (221210993) and next prime (221211017).

It can be written as a sum of positive squares in 2 ways, for example, as 174821284 + 46389721 = 13222^2 + 6811^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221211005 is a prime.

It is a super-2 number, since 2×221211005² = 97868617466220050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22121096 + ... + 22121105.

It is an arithmetic number, because the mean of its divisors is an integer number (66363303).

Almost surely, 2^221211005 is an apocalyptic number.

It is an amenable number.

221211005 is a deficient number, since it is larger than the sum of its proper divisors (44242207).

221211005 is an equidigital number, since it uses as much as digits as its factorization.

221211005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44242206.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 221211005 is about 14873.1639202962. The cubic root of 221211005 is about 604.7867153380.

Adding to 221211005 its reverse (500112122), we get a palindrome (721323127).

The spelling of 221211005 in words is "two hundred twenty-one million, two hundred eleven thousand, five".