21661457343822 has 72 divisors (see below), whose sum is σ = 50063205658752. Its totient is φ = 6767552793600.

The previous prime is 21661457343821. The next prime is 21661457343881. The reversal of 21661457343822 is 22834375416612.

21661457343822 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 1 + 4 + 573 + 43 + 8 + 22 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661457343821) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7385454 + ... + 9892817.

It is an arithmetic number, because the mean of its divisors is an integer number (695322300816).

Almost surely, 2^{21661457343822} is an apocalyptic number.

21661457343822 is an abundant number, since it is smaller than the sum of its proper divisors (28401748314930).

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

21661457343822 is a wasteful number, since it uses less digits than its factorization.

21661457343822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17278554 (or 17278534 counting only the distinct ones).

The product of its digits is 11612160, while the sum is 54.

The spelling of 21661457343822 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred fifty-seven million, three hundred forty-three thousand, eight hundred twenty-two".