21461217440 has 384 divisors, whose sum is σ = 59963016960. Its totient is φ = 7190249472.

The previous prime is 21461217439. The next prime is 21461217451. The reversal of 21461217440 is 4471216412.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 21461217397 and 21461217406.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 124053194 + ... + 124053366.

It is an arithmetic number, because the mean of its divisors is an integer number (156153690).

Almost surely, 2^21461217440 is an apocalyptic number.

21461217440 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 21461217440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29981508480).

21461217440 is an abundant number, since it is smaller than the sum of its proper divisors (38501799520).

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

21461217440 is a wasteful number, since it uses less digits than its factorization.

21461217440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 32.

The spelling of 21461217440 in words is "twenty-one billion, four hundred sixty-one million, two hundred seventeen thousand, four hundred forty".