21408203488 has 288 divisors, whose sum is σ = 54468288000. Its totient is φ = 8219667456.

The previous prime is 21408203461. The next prime is 21408203489. The reversal of 21408203488 is 88430280412.

It is a super-2 number, since 2×21408203488² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21408203488.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21408203489) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 107578813 + ... + 107579011.

It is an arithmetic number, because the mean of its divisors is an integer number (189126000).

Almost surely, 2^21408203488 is an apocalyptic number.

21408203488 is a gapful number since it is divisible by the number (28) 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 21408203488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27234144000).

21408203488 is an abundant number, since it is smaller than the sum of its proper divisors (33060084512).

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

21408203488 is a wasteful number, since it uses less digits than its factorization.

21408203488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 98304, while the sum is 40.

The spelling of 21408203488 in words is "twenty-one billion, four hundred eight million, two hundred three thousand, four hundred eighty-eight".