21144430240 has 48 divisors (see below), whose sum is σ = 50096982600. Its totient is φ = 8433515520.

The previous prime is 21144430157. The next prime is 21144430247. The reversal of 21144430240 is 4203444112.

It can be written as a sum of positive squares in 4 ways, for example, as 21005284624 + 139145616 = 144932^2 + 11796^2 .

It is not an unprimeable number, because it can be changed into a prime (21144430247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133491 + ... + 245170.

Almost surely, 2^21144430240 is an apocalyptic number.

21144430240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144430240 is an abundant number, since it is smaller than the sum of its proper divisors (28952552360).

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

21144430240 is a wasteful number, since it uses less digits than its factorization.

21144430240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379025 (or 379017 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21144430240 its reverse (4203444112), we get a palindrome (25347874352).

The spelling of 21144430240 in words is "twenty-one billion, one hundred forty-four million, four hundred thirty thousand, two hundred forty".