21124201540 has 96 divisors (see below), whose sum is σ = 48116839680. Its totient is φ = 7743859200.

The previous prime is 21124201523. The next prime is 21124201541. The reversal of 21124201540 is 4510242112.

It is not an unprimeable number, because it can be changed into a prime (21124201541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33477025 + ... + 33477655.

It is an arithmetic number, because the mean of its divisors is an integer number (501217080).

Almost surely, 2^21124201540 is an apocalyptic number.

21124201540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21124201540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24058419840).

21124201540 is an abundant number, since it is smaller than the sum of its proper divisors (26992638140).

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

21124201540 is a wasteful number, since it uses less digits than its factorization.

21124201540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373 (or 1371 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

Adding to 21124201540 its reverse (4510242112), we get a palindrome (25634443652).

The spelling of 21124201540 in words is "twenty-one billion, one hundred twenty-four million, two hundred one thousand, five hundred forty".