21216210516346 has 16 divisors (see below), whose sum is σ = 31847396632704. Its totient is φ = 10600412142384.

The previous prime is 21216210516341. The next prime is 21216210516373. The reversal of 21216210516346 is 64361501261212.

It is a junction number, because it is equal to n+sod(n) for n = 21216210516299 and 21216210516308.

It is not an unprimeable number, because it can be changed into a prime (21216210516341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97891276 + ... + 98107768.

It is an arithmetic number, because the mean of its divisors is an integer number (1990462289544).

Almost surely, 2^{21216210516346} is an apocalyptic number.

21216210516346 is a deficient number, since it is larger than the sum of its proper divisors (10631186116358).

21216210516346 is a wasteful number, since it uses less digits than its factorization.

21216210516346 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251805.

The product of its (nonzero) digits is 103680, while the sum is 40.

Adding to 21216210516346 its reverse (64361501261212), we get a palindrome (85577711777558).

The spelling of 21216210516346 in words is "twenty-one trillion, two hundred sixteen billion, two hundred ten million, five hundred sixteen thousand, three hundred forty-six".