21213566532 has 144 divisors (see below), whose sum is σ = 56124169920. Its totient is φ = 6749588736.

The previous prime is 21213566527. The next prime is 21213566533. The reversal of 21213566532 is 23566531212.

21213566532 is a `hidden beast` number, since 21 + 21 + 3 + 566 + 53 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21213566533) 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, 41676694 + ... + 41677202.

It is an arithmetic number, because the mean of its divisors is an integer number (389751180).

Almost surely, 2^21213566532 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 21213566532, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28062084960).

21213566532 is an abundant number, since it is smaller than the sum of its proper divisors (34910603388).

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

21213566532 is a wasteful number, since it uses less digits than its factorization.

21213566532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090 (or 1085 counting only the distinct ones).

The product of its digits is 64800, while the sum is 36.

It can be divided in two parts, 2121 and 3566532, that added together give a palindrome (3568653).

The spelling of 21213566532 in words is "twenty-one billion, two hundred thirteen million, five hundred sixty-six thousand, five hundred thirty-two".