1221020413440 has 80 divisors (see below), whose sum is σ = 3903449658768. Its totient is φ = 325605441536.

The previous prime is 1221020413427. The next prime is 1221020413489. The reversal of 1221020413440 is 443140201221.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1221020413440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79485837 + ... + 79501196.

Almost surely, 2^{1221020413440} is an apocalyptic number.

1221020413440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221020413440 is an abundant number, since it is smaller than the sum of its proper divisors (2682429245328).

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

1221020413440 is an equidigital number, since it uses as much as digits as its factorization.

1221020413440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158987059 (or 158987043 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 1221020413440 its reverse (443140201221), we get a palindrome (1664160614661).

The spelling of 1221020413440 in words is "one trillion, two hundred twenty-one billion, twenty million, four hundred thirteen thousand, four hundred forty".