1221153332520 has 64 divisors (see below), whose sum is σ = 3996501819840. Its totient is φ = 296037171200.

The previous prime is 1221153332489. The next prime is 1221153332533. The reversal of 1221153332520 is 252333511221.

It is a Harshad number since it is a multiple of its sum of digits (30).

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 15 ways as a sum of consecutive naturals, for example, 462556761 + ... + 462559400.

It is an arithmetic number, because the mean of its divisors is an integer number (62445340935).

Almost surely, 2^{1221153332520} is an apocalyptic number.

1221153332520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221153332520 is an abundant number, since it is smaller than the sum of its proper divisors (2775348487320).

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

1221153332520 is a wasteful number, since it uses less digits than its factorization.

1221153332520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 925116186 (or 925116182 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 30.

Adding to 1221153332520 its reverse (252333511221), we get a palindrome (1473486843741).

The spelling of 1221153332520 in words is "one trillion, two hundred twenty-one billion, one hundred fifty-three million, three hundred thirty-two thousand, five hundred twenty".