21966165504 has 240 divisors, whose sum is σ = 65775790080. Its totient is φ = 7049687040.

The previous prime is 21966165499. The next prime is 21966165527. The reversal of 21966165504 is 40556166912.

21966165504 is a `hidden beast` number, since 2 + 1 + 96 + 6 + 1 + 6 + 550 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21966165504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 52425007 + ... + 52425425.

It is an arithmetic number, because the mean of its divisors is an integer number (274065792).

Almost surely, 2^21966165504 is an apocalyptic number.

21966165504 is a gapful number since it is divisible by the number (24) 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 21966165504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32887895040).

21966165504 is an abundant number, since it is smaller than the sum of its proper divisors (43809624576).

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

21966165504 is a wasteful number, since it uses less digits than its factorization.

21966165504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 841 (or 822 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 21966165504 in words is "twenty-one billion, nine hundred sixty-six million, one hundred sixty-five thousand, five hundred four".