21525350221 has 8 divisors (see below), whose sum is σ = 21632198040. Its totient is φ = 21418747968.

The previous prime is 21525350201. The next prime is 21525350243. The reversal of 21525350221 is 12205352512.

It can be written as a sum of positive squares in 4 ways, for example, as 346369321 + 21178980900 = 18611^2 + 145530^2 .

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 21525350221 - 2²⁷ = 21391132493 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21525350221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21525350201) 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, 115615 + ... + 237523.

It is an arithmetic number, because the mean of its divisors is an integer number (2704024755).

Almost surely, 2^21525350221 is an apocalyptic number.

It is an amenable number.

21525350221 is a deficient number, since it is larger than the sum of its proper divisors (106847819).

21525350221 is a wasteful number, since it uses less digits than its factorization.

21525350221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122783.

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 21525350221 in words is "twenty-one billion, five hundred twenty-five million, three hundred fifty thousand, two hundred twenty-one".