21142403440 has 40 divisors (see below), whose sum is σ = 49778331840. Its totient is φ = 8349908736.

The previous prime is 21142403431. The next prime is 21142403449. The reversal of 21142403440 is 4430424112.

It is an interprime number because it is at equal distance from previous prime (21142403431) and next prime (21142403449).

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142403449) 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 7 ways as a sum of consecutive naturals, for example, 1666339 + ... + 1678978.

It is an arithmetic number, because the mean of its divisors is an integer number (1244458296).

Almost surely, 2^21142403440 is an apocalyptic number.

21142403440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21142403440 is an abundant number, since it is smaller than the sum of its proper divisors (28635928400).

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

21142403440 is a wasteful number, since it uses less digits than its factorization.

21142403440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3345409 (or 3345403 counting only the distinct ones).

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

Adding to 21142403440 its reverse (4430424112), we get a palindrome (25572827552).

The spelling of 21142403440 in words is "twenty-one billion, one hundred forty-two million, four hundred three thousand, four hundred forty".