1221787125 has 64 divisors (see below), whose sum is σ = 2432801280. Its totient is φ = 601473600.

The previous prime is 1221787121. The next prime is 1221787129. The reversal of 1221787125 is 5217871221.

It is an interprime number because it is at equal distance from previous prime (1221787121) and next prime (1221787129).

It is not a de Polignac number, because 1221787125 - 2² = 1221787121 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221787125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221787121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 29952 + ... + 57798.

It is an arithmetic number, because the mean of its divisors is an integer number (38012520).

Almost surely, 2^1221787125 is an apocalyptic number.

1221787125 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221787125 is a deficient number, since it is larger than the sum of its proper divisors (1211014155).

1221787125 is a wasteful number, since it uses less digits than its factorization.

1221787125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27884 (or 27868 counting only the distinct ones).

The product of its digits is 15680, while the sum is 36.

The square root of 1221787125 is about 34954.0716512397. The cubic root of 1221787125 is about 1069.0512231882.

The spelling of 1221787125 in words is "one billion, two hundred twenty-one million, seven hundred eighty-seven thousand, one hundred twenty-five".