21405936236832 has 576 divisors, whose sum is σ = 74461698178560. Its totient is φ = 5962062371328.

The previous prime is 21405936236777. The next prime is 21405936236879. The reversal of 21405936236832 is 23863263950412.

21405936236832 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 5 + 9 + 3 + 623 + 6 + 8 + 3 + 2 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 952083063 + ... + 952105545.

It is an arithmetic number, because the mean of its divisors is an integer number (129273781560).

Almost surely, 2^{21405936236832} 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 21405936236832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37230849089280).

21405936236832 is an abundant number, since it is smaller than the sum of its proper divisors (53055761941728).

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

21405936236832 is a wasteful number, since it uses less digits than its factorization.

21405936236832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23082 (or 23061 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 54.

The spelling of 21405936236832 in words is "twenty-one trillion, four hundred five billion, nine hundred thirty-six million, two hundred thirty-six thousand, eight hundred thirty-two".