21665140200 has 384 divisors, whose sum is σ = 84222288000. Its totient is φ = 5070643200.

The previous prime is 21665140177. The next prime is 21665140223. The reversal of 21665140200 is 204156612.

21665140200 is a `hidden beast` number, since 2 + 1 + 6 + 651 + 4 + 0 + 2 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21665140177) and next prime (21665140223).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1716312 + ... + 1728888.

It is an arithmetic number, because the mean of its divisors is an integer number (219328875).

Almost surely, 2^21665140200 is an apocalyptic number.

21665140200 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 21665140200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42111144000).

21665140200 is an abundant number, since it is smaller than the sum of its proper divisors (62557147800).

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

21665140200 is a wasteful number, since it uses less digits than its factorization.

21665140200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12642 (or 12627 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21665140200 its reverse (204156612), we get a palindrome (21869296812).

The spelling of 21665140200 in words is "twenty-one billion, six hundred sixty-five million, one hundred forty thousand, two hundred".