21324212640 has 144 divisors (see below), whose sum is σ = 75932857728. Its totient is φ = 5439211008.

The previous prime is 21324212621. The next prime is 21324212669. The reversal of 21324212640 is 4621242312.

21324212640 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 4 + 2 + 12 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 288804 + ... + 355043.

It is an arithmetic number, because the mean of its divisors is an integer number (527311512).

Almost surely, 2^21324212640 is an apocalyptic number.

21324212640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21324212640 is an abundant number, since it is smaller than the sum of its proper divisors (54608645088).

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

21324212640 is a wasteful number, since it uses less digits than its factorization.

21324212640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643891 (or 643880 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

Adding to 21324212640 its reverse (4621242312), we get a palindrome (25945454952).

The spelling of 21324212640 in words is "twenty-one billion, three hundred twenty-four million, two hundred twelve thousand, six hundred forty".