21406247545650 has 192 divisors, whose sum is σ = 58003828517376. Its totient is φ = 5181318144000.

The previous prime is 21406247545619. The next prime is 21406247545651. The reversal of 21406247545650 is 5654574260412.

It is a junction number, because it is equal to n+sod(n) for n = 21406247545593 and 21406247545602.

It is not an unprimeable number, because it can be changed into a prime (21406247545651) 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, 3673628037 + ... + 3673633863.

It is an arithmetic number, because the mean of its divisors is an integer number (302103273528).

Almost surely, 2^{21406247545650} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21406247545650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29001914258688).

21406247545650 is an abundant number, since it is smaller than the sum of its proper divisors (36597580971726).

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

21406247545650 is a wasteful number, since it uses less digits than its factorization.

21406247545650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8937 (or 8932 counting only the distinct ones).

The product of its (nonzero) digits is 8064000, while the sum is 51.

The spelling of 21406247545650 in words is "twenty-one trillion, four hundred six billion, two hundred forty-seven million, five hundred forty-five thousand, six hundred fifty".