21621272135242 has 16 divisors (see below), whose sum is σ = 34972566160392. Its totient is φ = 9965935595520.

The previous prime is 21621272135237. The next prime is 21621272135261. The reversal of 21621272135242 is 24253127212612.

It can be written as a sum of positive squares in 4 ways, for example, as 4537756300401 + 17083515834841 = 2130201^2 + 4133221^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21621272135195 and 21621272135204.

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, 546358263 + ... + 546397834.

Almost surely, 2^{21621272135242} is an apocalyptic number.

21621272135242 is a deficient number, since it is larger than the sum of its proper divisors (13351294025150).

21621272135242 is a wasteful number, since it uses less digits than its factorization.

21621272135242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1092756873.

The product of its digits is 161280, while the sum is 40.

Adding to 21621272135242 its reverse (24253127212612), we get a palindrome (45874399347854).

The spelling of 21621272135242 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-two million, one hundred thirty-five thousand, two hundred forty-two".