1221522665 has 8 divisors (see below), whose sum is σ = 1599084288. Its totient is φ = 888380080.

The previous prime is 1221522619. The next prime is 1221522683. The reversal of 1221522665 is 5662251221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221522665 - 2¹⁶ = 1221457129 is a prime.

It is a super-2 number, since 2×1221522665² = 2984235242217404450, which contains 22 as substring.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 11104697 + ... + 11104806.

It is an arithmetic number, because the mean of its divisors is an integer number (199885536).

Almost surely, 2^1221522665 is an apocalyptic number.

It is an amenable number.

1221522665 is a deficient number, since it is larger than the sum of its proper divisors (377561623).

1221522665 is a wasteful number, since it uses less digits than its factorization.

1221522665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22209519.

The product of its digits is 14400, while the sum is 32.

The square root of 1221522665 is about 34950.2884823573. The cubic root of 1221522665 is about 1068.9740843583.

Adding to 1221522665 its reverse (5662251221), we get a palindrome (6883773886).

The spelling of 1221522665 in words is "one billion, two hundred twenty-one million, five hundred twenty-two thousand, six hundred sixty-five".