21216236400513 has 72 divisors (see below), whose sum is σ = 38977664502816. Its totient is φ = 10996541337600.

The previous prime is 21216236400511. The next prime is 21216236400517. The reversal of 21216236400513 is 31500463261212.

21216236400513 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 6 + 2 + 3 + 640 + 0 + 5 + 1 + 3 = 666.

It is not a de Polignac number, because 21216236400513 - 2¹ = 21216236400511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21216236400511) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2787328 + ... + 7085313.

It is an arithmetic number, because the mean of its divisors is an integer number (541356451428).

Almost surely, 2^{21216236400513} is an apocalyptic number.

It is an amenable number.

21216236400513 is a deficient number, since it is larger than the sum of its proper divisors (17761428102303).

21216236400513 is a wasteful number, since it uses less digits than its factorization.

21216236400513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9873115 (or 9873105 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

Adding to 21216236400513 its reverse (31500463261212), we get a palindrome (52716699661725).

The spelling of 21216236400513 in words is "twenty-one trillion, two hundred sixteen billion, two hundred thirty-six million, four hundred thousand, five hundred thirteen".