1225221216 has 24 divisors (see below), whose sum is σ = 3216205944. Its totient is φ = 408407040.

The previous prime is 1225221211. The next prime is 1225221253. The reversal of 1225221216 is 6121225221.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225221211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6381265 + ... + 6381456.

It is an arithmetic number, because the mean of its divisors is an integer number (134008581).

Almost surely, 2^1225221216 is an apocalyptic number.

1225221216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1225221216 is an abundant number, since it is smaller than the sum of its proper divisors (1990984728).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1225221216 is a wasteful number, since it uses less digits than its factorization.

1225221216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12762734 (or 12762726 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

The square root of 1225221216 is about 35003.1600859122. The cubic root of 1225221216 is about 1070.0518844029.

Adding to 1225221216 its reverse (6121225221), we get a palindrome (7346446437).

The spelling of 1225221216 in words is "one billion, two hundred twenty-five million, two hundred twenty-one thousand, two hundred sixteen".