1221405121244 has 96 divisors (see below), whose sum is σ = 2736366796800. Its totient is φ = 463263975360.

The previous prime is 1221405121229. The next prime is 1221405121249. The reversal of 1221405121244 is 4421215041221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221405121249) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1545437 + ... + 2197995.

It is an arithmetic number, because the mean of its divisors is an integer number (28503820800).

Almost surely, 2^{1221405121244} is an apocalyptic number.

1221405121244 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221405121244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1368183398400).

1221405121244 is an abundant number, since it is smaller than the sum of its proper divisors (1514961675556).

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

1221405121244 is a wasteful number, since it uses less digits than its factorization.

1221405121244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 652743 (or 652741 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 29.

The spelling of 1221405121244 in words is "one trillion, two hundred twenty-one billion, four hundred five million, one hundred twenty-one thousand, two hundred forty-four".