2121542921680 has 240 divisors, whose sum is σ = 6218667136080. Its totient is φ = 667154202624.

The previous prime is 2121542921677. The next prime is 2121542921713. The reversal of 2121542921680 is 861292451212.

It can be written as a sum of positive squares in 8 ways, for example, as 16095489424 + 2105447432256 = 126868^2 + 1451016^2 .

It is a super-2 number, since 2×2121542921680² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7868136 + ... + 8133304.

It is an arithmetic number, because the mean of its divisors is an integer number (25911113067).

Almost surely, 2^{2121542921680} is an apocalyptic number.

2121542921680 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 2121542921680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3109333568040).

2121542921680 is an abundant number, since it is smaller than the sum of its proper divisors (4097124214400).

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

2121542921680 is a wasteful number, since it uses less digits than its factorization.

2121542921680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265366 (or 265353 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 43.

The spelling of 2121542921680 in words is "two trillion, one hundred twenty-one billion, five hundred forty-two million, nine hundred twenty-one thousand, six hundred eighty".