2121666451440 has 160 divisors (see below), whose sum is σ = 6786092805120. Its totient is φ = 548075793408.

The previous prime is 2121666451439. The next prime is 2121666451447. The reversal of 2121666451440 is 441546661212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 2121666451392 and 2121666451401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121666451447) 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, 50802 + ... + 2060561.

It is an arithmetic number, because the mean of its divisors is an integer number (42413080032).

Almost surely, 2^{2121666451440} is an apocalyptic number.

2121666451440 is a gapful number since it is divisible by the number (20) 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 2121666451440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3393046402560).

2121666451440 is an abundant number, since it is smaller than the sum of its proper divisors (4664426353680).

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

2121666451440 is a wasteful number, since it uses less digits than its factorization.

2121666451440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2111511 (or 2111505 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 42.

The spelling of 2121666451440 in words is "two trillion, one hundred twenty-one billion, six hundred sixty-six million, four hundred fifty-one thousand, four hundred forty".