912221209 has 3 divisors (see below), whose sum is σ = 912251413. Its totient is φ = 912191006.

The previous prime is 912221203. The next prime is 912221227. The reversal of 912221209 is 902122219.

The square root of 912221209 is 30203.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 902122219 = 20147 ⋅44777.

It is not a de Polignac number, because 912221209 - 2³ = 912221201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (912221201) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 15102 + ... + 45304.

Almost surely, 2^912221209 is an apocalyptic number.

912221209 is the 30203-rd square number.

912221209 is the 15102-nd centered octagonal number.

It is an amenable number.

912221209 is a deficient number, since it is larger than the sum of its proper divisors (30204).

912221209 is an frugal number, since it uses more digits than its factorization.

912221209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60406 (or 30203 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 28.

The cubic root of 912221209 is about 969.8399172533.

Multiplying 912221209 by its product of nonzero digits (1296), we get a square (1182238686864 = 1087308²).

The spelling of 912221209 in words is "nine hundred twelve million, two hundred twenty-one thousand, two hundred nine".