1321866295890 has 384 divisors, whose sum is σ = 3981809664000. Its totient is φ = 274742641152.

The previous prime is 1321866295751. The next prime is 1321866295901. The reversal of 1321866295890 is 985926681231.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 393528031 + ... + 393531389.

It is an arithmetic number, because the mean of its divisors is an integer number (10369296000).

Almost surely, 2^{1321866295890} is an apocalyptic number.

1321866295890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1321866295890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1990904832000).

1321866295890 is an abundant number, since it is smaller than the sum of its proper divisors (2659943368110).

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

1321866295890 is a wasteful number, since it uses less digits than its factorization.

1321866295890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3622 (or 3603 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 60.

The spelling of 1321866295890 in words is "one trillion, three hundred twenty-one billion, eight hundred sixty-six million, two hundred ninety-five thousand, eight hundred ninety".