21243420142 has 16 divisors (see below), whose sum is σ = 36427121280. Its totient is φ = 9101865528.

The previous prime is 21243420139. The next prime is 21243420169. The reversal of 21243420142 is 24102434212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150568 + ... + 255259.

It is an arithmetic number, because the mean of its divisors is an integer number (2276695080).

Almost surely, 2^21243420142 is an apocalyptic number.

21243420142 is a deficient number, since it is larger than the sum of its proper divisors (15183701138).

21243420142 is a wasteful number, since it uses less digits than its factorization.

21243420142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409575.

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

Adding to 21243420142 its reverse (24102434212), we get a palindrome (45345854354).

The spelling of 21243420142 in words is "twenty-one billion, two hundred forty-three million, four hundred twenty thousand, one hundred forty-two".