21201333540 has 48 divisors (see below), whose sum is σ = 62488144320. Its totient is φ = 5356126080.

The previous prime is 21201333529. The next prime is 21201333547. The reversal of 21201333540 is 4533310212.

It is a self number, because there is not a number n which added to its sum of digits gives 21201333540.

It is not an unprimeable number, because it can be changed into a prime (21201333547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9297691 + ... + 9299970.

It is an arithmetic number, because the mean of its divisors is an integer number (1301836340).

Almost surely, 2^21201333540 is an apocalyptic number.

21201333540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201333540 is an abundant number, since it is smaller than the sum of its proper divisors (41286810780).

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

21201333540 is a wasteful number, since it uses less digits than its factorization.

21201333540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18597692 (or 18597690 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

Adding to 21201333540 its reverse (4533310212), we get a palindrome (25734643752).

The spelling of 21201333540 in words is "twenty-one billion, two hundred one million, three hundred thirty-three thousand, five hundred forty".