1311221520520 has 32 divisors (see below), whose sum is σ = 2950421584320. Its totient is φ = 524457823680.

The previous prime is 1311221520491. The next prime is 1311221520529. The reversal of 1311221520520 is 250251221131.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1311221520529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 265782 + ... + 1641061.

It is an arithmetic number, because the mean of its divisors is an integer number (92200674510).

Almost surely, 2^{1311221520520} is an apocalyptic number.

1311221520520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1311221520520 is an abundant number, since it is smaller than the sum of its proper divisors (1639200063800).

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

1311221520520 is a wasteful number, since it uses less digits than its factorization.

1311221520520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1924045 (or 1924041 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

Adding to 1311221520520 its reverse (250251221131), we get a palindrome (1561472741651).

The spelling of 1311221520520 in words is "one trillion, three hundred eleven billion, two hundred twenty-one million, five hundred twenty thousand, five hundred twenty".