21621405006240 has 384 divisors, whose sum is σ = 73828454918400. Its totient is φ = 5287246036992.

The previous prime is 21621405006181. The next prime is 21621405006301. The reversal of 21621405006240 is 4260050412612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4626876544 + ... + 4626881216.

It is an arithmetic number, because the mean of its divisors is an integer number (192261601350).

Almost surely, 2^{21621405006240} is an apocalyptic number.

21621405006240 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 21621405006240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36914227459200).

21621405006240 is an abundant number, since it is smaller than the sum of its proper divisors (52207049912160).

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

21621405006240 is a wasteful number, since it uses less digits than its factorization.

21621405006240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9416 (or 9408 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

Adding to 21621405006240 its reverse (4260050412612), we get a palindrome (25881455418852).

The spelling of 21621405006240 in words is "twenty-one trillion, six hundred twenty-one billion, four hundred five million, six thousand, two hundred forty".