21666705399300 has 576 divisors, whose sum is σ = 70340681908224. Its totient is φ = 5115466137600.

The previous prime is 21666705399299. The next prime is 21666705399323. The reversal of 21666705399300 is 399350766612.

It is a happy number.

It is a super-2 number, since 2×21666705399300² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1831344385 + ... + 1831356215.

It is an arithmetic number, because the mean of its divisors is an integer number (122119239424).

Almost surely, 2^{21666705399300} is an apocalyptic number.

21666705399300 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 21666705399300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35170340954112).

21666705399300 is an abundant number, since it is smaller than the sum of its proper divisors (48673976508924).

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

21666705399300 is a wasteful number, since it uses less digits than its factorization.

21666705399300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12108 (or 12101 counting only the distinct ones).

The product of its (nonzero) digits is 11022480, while the sum is 57.

The spelling of 21666705399300 in words is "twenty-one trillion, six hundred sixty-six billion, seven hundred five million, three hundred ninety-nine thousand, three hundred".