21666201034968 has 384 divisors, whose sum is σ = 70463814451200. Its totient is φ = 6042458055168.

The previous prime is 21666201034909. The next prime is 21666201034987. The reversal of 21666201034968 is 86943010266612.

It is a super-2 number, since 2×21666201034968² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1279214596 + ... + 1279231532.

It is an arithmetic number, because the mean of its divisors is an integer number (183499516800).

Almost surely, 2^{21666201034968} is an apocalyptic number.

21666201034968 is a gapful number since it is divisible by the number (28) 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 21666201034968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35231907225600).

21666201034968 is an abundant number, since it is smaller than the sum of its proper divisors (48797613416232).

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

21666201034968 is a wasteful number, since it uses less digits than its factorization.

21666201034968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17436 (or 17379 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 54.

The spelling of 21666201034968 in words is "twenty-one trillion, six hundred sixty-six billion, two hundred one million, thirty-four thousand, nine hundred sixty-eight".