21216438410 has 16 divisors (see below), whose sum is σ = 38198069856. Its totient is φ = 8484690768.

The previous prime is 21216438359. The next prime is 21216438443. The reversal of 21216438410 is 1483461212.

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, 187832 + ... + 278771.

It is an arithmetic number, because the mean of its divisors is an integer number (2387379366).

Almost surely, 2^21216438410 is an apocalyptic number.

21216438410 is a deficient number, since it is larger than the sum of its proper divisors (16981631446).

21216438410 is a wasteful number, since it uses less digits than its factorization.

21216438410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471157.

The product of its (nonzero) digits is 9216, while the sum is 32.

Adding to 21216438410 its reverse (1483461212), we get a palindrome (22699899622).

The spelling of 21216438410 in words is "twenty-one billion, two hundred sixteen million, four hundred thirty-eight thousand, four hundred ten".