21501344000 has 72 divisors (see below), whose sum is σ = 53562615288. Its totient is φ = 8600524800.

The previous prime is 21501343999. The next prime is 21501344003. The reversal of 21501344000 is 44310512.

It can be written as a sum of positive squares in 4 ways, for example, as 409010176 + 21092333824 = 20224^2 + 145232^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21501344003) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 303959 + ... + 367958.

Almost surely, 2^21501344000 is an apocalyptic number.

21501344000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21501344000 is an abundant number, since it is smaller than the sum of its proper divisors (32061271288).

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

21501344000 is an frugal number, since it uses more digits than its factorization.

21501344000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671948 (or 671924 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 21501344000 its reverse (44310512), we get a palindrome (21545654512).

The spelling of 21501344000 in words is "twenty-one billion, five hundred one million, three hundred forty-four thousand".