21144305240 has 16 divisors (see below), whose sum is σ = 47574686880. Its totient is φ = 8457722080.

The previous prime is 21144305167. The next prime is 21144305243. The reversal of 21144305240 is 4250344112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144305243) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264303776 + ... + 264303855.

It is an arithmetic number, because the mean of its divisors is an integer number (2973417930).

Almost surely, 2^21144305240 is an apocalyptic number.

21144305240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144305240 is an abundant number, since it is smaller than the sum of its proper divisors (26430381640).

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

21144305240 is a wasteful number, since it uses less digits than its factorization.

21144305240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528607642 (or 528607638 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21144305240 its reverse (4250344112), we get a palindrome (25394649352).

The spelling of 21144305240 in words is "twenty-one billion, one hundred forty-four million, three hundred five thousand, two hundred forty".