21496409856 has 432 divisors, whose sum is σ = 67711408128. Its totient is φ = 6793113600.

The previous prime is 21496409833. The next prime is 21496409863. The reversal of 21496409856 is 65890469412.

21496409856 is a `hidden beast` number, since 21 + 496 + 40 + 98 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 136919730 + ... + 136919886.

Almost surely, 2^21496409856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21496409856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33855704064).

21496409856 is an abundant number, since it is smaller than the sum of its proper divisors (46214998272).

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

21496409856 is an equidigital number, since it uses as much as digits as its factorization.

21496409856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290 (or 264 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 21496409856 in words is "twenty-one billion, four hundred ninety-six million, four hundred nine thousand, eight hundred fifty-six".