21216042121354 has 16 divisors (see below), whose sum is σ = 31923689020416. Its totient is φ = 10574852245200.

The previous prime is 21216042121349. The next prime is 21216042121367. The reversal of 21216042121354 is 45312124061212.

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, 8882202 + ... + 11014789.

It is an arithmetic number, because the mean of its divisors is an integer number (1995230563776).

Almost surely, 2^{21216042121354} is an apocalyptic number.

21216042121354 is a deficient number, since it is larger than the sum of its proper divisors (10707646899062).

21216042121354 is a wasteful number, since it uses less digits than its factorization.

21216042121354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19898661.

The product of its (nonzero) digits is 23040, while the sum is 34.

Adding to 21216042121354 its reverse (45312124061212), we get a palindrome (66528166182566).

The spelling of 21216042121354 in words is "twenty-one trillion, two hundred sixteen billion, forty-two million, one hundred twenty-one thousand, three hundred fifty-four".