1217523221 has 16 divisors (see below), whose sum is σ = 1326251376. Its totient is φ = 1113025536.

The previous prime is 1217523169. The next prime is 1217523283. The reversal of 1217523221 is 1223257121.

It can be written as a sum of positive squares in 8 ways, for example, as 183900721 + 1033622500 = 13561^2 + 32150^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217523221 - 2¹⁰ = 1217522197 is a prime.

It is a super-3 number, since 3×1217523221³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217523421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 474875 + ... + 477431.

It is an arithmetic number, because the mean of its divisors is an integer number (82890711).

Almost surely, 2^1217523221 is an apocalyptic number.

It is an amenable number.

1217523221 is a deficient number, since it is larger than the sum of its proper divisors (108728155).

1217523221 is a wasteful number, since it uses less digits than its factorization.

1217523221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3368.

The product of its digits is 1680, while the sum is 26.

The square root of 1217523221 is about 34893.0253919032. The cubic root of 1217523221 is about 1067.8061495601.

The spelling of 1217523221 in words is "one billion, two hundred seventeen million, five hundred twenty-three thousand, two hundred twenty-one".