21254317221 has 16 divisors (see below), whose sum is σ = 29705417280. Its totient is φ = 13502455680.

The previous prime is 21254317219. The next prime is 21254317237. The reversal of 21254317221 is 12271345212.

It is not a de Polignac number, because 21254317221 - 2¹ = 21254317219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254317211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2004006 + ... + 2014583.

It is an arithmetic number, because the mean of its divisors is an integer number (1856588580).

Almost surely, 2^21254317221 is an apocalyptic number.

It is an amenable number.

21254317221 is a deficient number, since it is larger than the sum of its proper divisors (8451100059).

21254317221 is a wasteful number, since it uses less digits than its factorization.

21254317221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4018676.

The product of its digits is 6720, while the sum is 30.

The spelling of 21254317221 in words is "twenty-one billion, two hundred fifty-four million, three hundred seventeen thousand, two hundred twenty-one".