21408883868736 has 3136 divisors, whose sum is σ = 85967762227200. Its totient is φ = 5135593881600.

The previous prime is 21408883868731. The next prime is 21408883868737. The reversal of 21408883868736 is 63786838880412.

21408883868736 is a `hidden beast` number, since 2 + 1 + 408 + 88 + 38 + 6 + 87 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (21408883868731) by changing a digit.

It is a polite number, since it can be written in 447 ways as a sum of consecutive naturals, for example, 270998529945 + ... + 270998530023.

Almost surely, 2^{21408883868736} is an apocalyptic number.

21408883868736 is a gapful number since it is divisible by the number (26) 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 21408883868736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42983881113600).

21408883868736 is an abundant number, since it is smaller than the sum of its proper divisors (64558878358464).

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

21408883868736 is a wasteful number, since it uses less digits than its factorization.

21408883868736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260 (or 235 counting only the distinct ones).

The product of its (nonzero) digits is 594542592, while the sum is 72.

The spelling of 21408883868736 in words is "twenty-one trillion, four hundred eight billion, eight hundred eighty-three million, eight hundred sixty-eight thousand, seven hundred thirty-six".