1221525320 has 32 divisors (see below), whose sum is σ = 2764334520. Its totient is φ = 485783040.

The previous prime is 1221525299. The next prime is 1221525323. The reversal of 1221525320 is 235251221.

It can be written as a sum of positive squares in 4 ways, for example, as 1196744836 + 24780484 = 34594^2 + 4978^2 .

It is a super-3 number, since 3×1221525320³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (1221525323) by changing a digit.

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, 81341 + ... + 95180.

Almost surely, 2^1221525320 is an apocalyptic number.

1221525320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221525320 is an abundant number, since it is smaller than the sum of its proper divisors (1542809200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221525320 is a wasteful number, since it uses less digits than its factorization.

1221525320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176705 (or 176701 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 1221525320 is about 34950.3264648558. The cubic root of 1221525320 is about 1068.9748588354.

Adding to 1221525320 its reverse (235251221), we get a palindrome (1456776541).

The spelling of 1221525320 in words is "one billion, two hundred twenty-one million, five hundred twenty-five thousand, three hundred twenty".