21243125542 has 8 divisors (see below), whose sum is σ = 33250109616. Its totient is φ = 10159755672.

The previous prime is 21243125539. The next prime is 21243125543. The reversal of 21243125542 is 24552134212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243125543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 230903493 + ... + 230903584.

It is an arithmetic number, because the mean of its divisors is an integer number (4156263702).

Almost surely, 2^21243125542 is an apocalyptic number.

21243125542 is a deficient number, since it is larger than the sum of its proper divisors (12006984074).

21243125542 is a wasteful number, since it uses less digits than its factorization.

21243125542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 461807102.

The product of its digits is 19200, while the sum is 31.

Adding to 21243125542 its reverse (24552134212), we get a palindrome (45795259754).

The spelling of 21243125542 in words is "twenty-one billion, two hundred forty-three million, one hundred twenty-five thousand, five hundred forty-two".