21854204221 has 8 divisors (see below), whose sum is σ = 22751800920. Its totient is φ = 20966207808.

The previous prime is 21854204189. The next prime is 21854204227. The reversal of 21854204221 is 12240245812.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1676001721 + 20178202500 = 40939^2 + 142050^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21854204221 - 2⁵ = 21854204189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854204227) 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, 2395426 + ... + 2404531.

It is an arithmetic number, because the mean of its divisors is an integer number (2843975115).

Almost surely, 2^21854204221 is an apocalyptic number.

It is an amenable number.

21854204221 is a deficient number, since it is larger than the sum of its proper divisors (897596699).

21854204221 is a wasteful number, since it uses less digits than its factorization.

21854204221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4800143.

The product of its (nonzero) digits is 10240, while the sum is 31.

The spelling of 21854204221 in words is "twenty-one billion, eight hundred fifty-four million, two hundred four thousand, two hundred twenty-one".