21358453221 has 16 divisors (see below), whose sum is σ = 36162460800. Its totient is φ = 12204830304.

The previous prime is 21358453187. The next prime is 21358453229. The reversal of 21358453221 is 12235485312.

21358453221 is a `hidden beast` number, since 2 + 1 + 3 + 584 + 53 + 2 + 21 = 666.

It is not a de Polignac number, because 21358453221 - 2¹⁴ = 21358436837 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21358453229) 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, 56503656 + ... + 56504033.

It is an arithmetic number, because the mean of its divisors is an integer number (2260153800).

Almost surely, 2^21358453221 is an apocalyptic number.

21358453221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21358453221 is a deficient number, since it is larger than the sum of its proper divisors (14804007579).

21358453221 is a wasteful number, since it uses less digits than its factorization.

21358453221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113007705 (or 113007699 counting only the distinct ones).

The product of its digits is 57600, while the sum is 36.

The spelling of 21358453221 in words is "twenty-one billion, three hundred fifty-eight million, four hundred fifty-three thousand, two hundred twenty-one".