1221013311320 has 64 divisors (see below), whose sum is σ = 2997309722400. Its totient is φ = 443963796480.

The previous prime is 1221013311307. The next prime is 1221013311337. The reversal of 1221013311320 is 231133101221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 1221013311292 and 1221013311301.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4856876 + ... + 5102084.

Almost surely, 2^{1221013311320} is an apocalyptic number.

1221013311320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221013311320 is an abundant number, since it is smaller than the sum of its proper divisors (1776296411080).

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

1221013311320 is a wasteful number, since it uses less digits than its factorization.

1221013311320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256548 (or 256544 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 1221013311320 its reverse (231133101221), we get a palindrome (1452146412541).

The spelling of 1221013311320 in words is "one trillion, two hundred twenty-one billion, thirteen million, three hundred eleven thousand, three hundred twenty".