21254134216 has 64 divisors (see below), whose sum is σ = 47605582080. Its totient is φ = 8698060800.

The previous prime is 21254134199. The next prime is 21254134219. The reversal of 21254134216 is 61243145212.

It is not an unprimeable number, because it can be changed into a prime (21254134219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 760360 + ... + 787816.

It is an arithmetic number, because the mean of its divisors is an integer number (743837220).

Almost surely, 2^21254134216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21254134216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23802791040).

21254134216 is an abundant number, since it is smaller than the sum of its proper divisors (26351447864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21254134216 is a wasteful number, since it uses less digits than its factorization.

21254134216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28094 (or 28090 counting only the distinct ones).

The product of its digits is 11520, while the sum is 31.

Adding to 21254134216 its reverse (61243145212), we get a palindrome (82497279428).

The spelling of 21254134216 in words is "twenty-one billion, two hundred fifty-four million, one hundred thirty-four thousand, two hundred sixteen".