21366805650 has 96 divisors (see below), whose sum is σ = 55600691328. Its totient is φ = 5419814400.

The previous prime is 21366805639. The next prime is 21366805667. The reversal of 21366805650 is 5650866312.

It is a happy number.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 607342 + ... + 641558.

It is an arithmetic number, because the mean of its divisors is an integer number (579173868).

Almost surely, 2^21366805650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21366805650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27800345664).

21366805650 is an abundant number, since it is smaller than the sum of its proper divisors (34233885678).

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

21366805650 is a wasteful number, since it uses less digits than its factorization.

21366805650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34436 (or 34431 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 42.

The spelling of 21366805650 in words is "twenty-one billion, three hundred sixty-six million, eight hundred five thousand, six hundred fifty".