21344877666 has 192 divisors, whose sum is σ = 56771020800. Its totient is φ = 5660990208.

The previous prime is 21344877643. The next prime is 21344877667. The reversal of 21344877666 is 66677844312.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21344877667) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 26383870 + ... + 26384678.

It is an arithmetic number, because the mean of its divisors is an integer number (295682400).

Almost surely, 2^21344877666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21344877666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28385510400).

21344877666 is an abundant number, since it is smaller than the sum of its proper divisors (35426143134).

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

21344877666 is a wasteful number, since it uses less digits than its factorization.

21344877666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1053 (or 1050 counting only the distinct ones).

The product of its digits is 8128512, while the sum is 54.

The spelling of 21344877666 in words is "twenty-one billion, three hundred forty-four million, eight hundred seventy-seven thousand, six hundred sixty-six".