21621344451272 has 32 divisors (see below), whose sum is σ = 41955596897400. Its totient is φ = 10433498955264.

The previous prime is 21621344451253. The next prime is 21621344451293. The reversal of 21621344451272 is 27215444312612.

It can be written as a sum of positive squares in 4 ways, for example, as 12836842785316 + 8784501665956 = 3582854^2 + 2963866^2 .

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, 19052123 + ... + 20155050.

Almost surely, 2^{21621344451272} is an apocalyptic number.

It is an amenable number.

21621344451272 is a deficient number, since it is larger than the sum of its proper divisors (20334252446128).

21621344451272 is a wasteful number, since it uses less digits than its factorization.

21621344451272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39209585 (or 39209581 counting only the distinct ones).

The product of its digits is 645120, while the sum is 44.

Adding to 21621344451272 its reverse (27215444312612), we get a palindrome (48836788763884).

The spelling of 21621344451272 in words is "twenty-one trillion, six hundred twenty-one billion, three hundred forty-four million, four hundred fifty-one thousand, two hundred seventy-two".