21216352015604 has 24 divisors (see below), whose sum is σ = 37420664161608. Its totient is φ = 10525057733120.

The previous prime is 21216352015603. The next prime is 21216352015619. The reversal of 21216352015604 is 40651025361212.

It can be written as a sum of positive squares in 4 ways, for example, as 2183898751204 + 19032453264400 = 1477802^2 + 4362620^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216352015603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40244027 + ... + 40767810.

It is an arithmetic number, because the mean of its divisors is an integer number (1559194340067).

Almost surely, 2^{21216352015604} is an apocalyptic number.

It is an amenable number.

21216352015604 is a deficient number, since it is larger than the sum of its proper divisors (16204312146004).

21216352015604 is a wasteful number, since it uses less digits than its factorization.

21216352015604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81012355 (or 81012353 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 38.

Adding to 21216352015604 its reverse (40651025361212), we get a palindrome (61867377376816).

The spelling of 21216352015604 in words is "twenty-one trillion, two hundred sixteen billion, three hundred fifty-two million, fifteen thousand, six hundred four".