21424433240 has 64 divisors (see below), whose sum is σ = 56991124800. Its totient is φ = 7092223488.

The previous prime is 21424433227. The next prime is 21424433249. The reversal of 21424433240 is 4233442412.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424433249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1311119 + ... + 1327358.

It is an arithmetic number, because the mean of its divisors is an integer number (890486325).

Almost surely, 2^21424433240 is an apocalyptic number.

21424433240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21424433240 is an abundant number, since it is smaller than the sum of its proper divisors (35566691560).

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

21424433240 is a wasteful number, since it uses less digits than its factorization.

21424433240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638524 (or 2638520 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 29.

Adding to 21424433240 its reverse (4233442412), we get a palindrome (25657875652).

The spelling of 21424433240 in words is "twenty-one billion, four hundred twenty-four million, four hundred thirty-three thousand, two hundred forty".