1217721025 has 24 divisors (see below), whose sum is σ = 1533886200. Its totient is φ = 958863360.

The previous prime is 1217720989. The next prime is 1217721031. The reversal of 1217721025 is 5201277121.

It can be written as a sum of positive squares in 12 ways, for example, as 269361 + 1217451664 = 519^2 + 34892^2 .

It is not a de Polignac number, because 1217721025 - 2¹⁹ = 1217196737 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1217720984 and 1217721002.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 476451 + ... + 478999.

It is an arithmetic number, because the mean of its divisors is an integer number (63911925).

Almost surely, 2^1217721025 is an apocalyptic number.

It is an amenable number.

1217721025 is a deficient number, since it is larger than the sum of its proper divisors (316165175).

1217721025 is a wasteful number, since it uses less digits than its factorization.

1217721025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2853 (or 2848 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 28.

The square root of 1217721025 is about 34895.8597114328. The cubic root of 1217721025 is about 1067.8639732047.

Adding to 1217721025 its reverse (5201277121), we get a palindrome (6418998146).

The spelling of 1217721025 in words is "one billion, two hundred seventeen million, seven hundred twenty-one thousand, twenty-five".