21203240242 has 8 divisors (see below), whose sum is σ = 33675734556. Its totient is φ = 9977995392.

The previous prime is 21203240231. The next prime is 21203240281. The reversal of 21203240242 is 24204230212.

It can be written as a sum of positive squares in 2 ways, for example, as 16098280641 + 5104959601 = 126879^2 + 71449^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 311812323 + ... + 311812390.

Almost surely, 2^21203240242 is an apocalyptic number.

21203240242 is a deficient number, since it is larger than the sum of its proper divisors (12472494314).

21203240242 is a wasteful number, since it uses less digits than its factorization.

21203240242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623624732.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21203240242 its reverse (24204230212), we get a palindrome (45407470454).

The spelling of 21203240242 in words is "twenty-one billion, two hundred three million, two hundred forty thousand, two hundred forty-two".