1221811125 has 16 divisors (see below), whose sum is σ = 2033094336. Its totient is φ = 651632400.

The previous prime is 1221811103. The next prime is 1221811133. The reversal of 1221811125 is 5211181221.

It is not a de Polignac number, because 1221811125 - 2⁶ = 1221811061 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221811095 and 1221811104.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1628707 + ... + 1629456.

It is an arithmetic number, because the mean of its divisors is an integer number (127068396).

Almost surely, 2^1221811125 is an apocalyptic number.

1221811125 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221811125 is a deficient number, since it is larger than the sum of its proper divisors (811283211).

1221811125 is an equidigital number, since it uses as much as digits as its factorization.

1221811125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3258181 (or 3258171 counting only the distinct ones).

The product of its digits is 320, while the sum is 24.

The square root of 1221811125 is about 34954.4149571982. The cubic root of 1221811125 is about 1069.0582230604.

Adding to 1221811125 its reverse (5211181221), we get a palindrome (6432992346).

The spelling of 1221811125 in words is "one billion, two hundred twenty-one million, eight hundred eleven thousand, one hundred twenty-five".