21652551221 has 8 divisors (see below), whose sum is σ = 26048182080. Its totient is φ = 17582522688.

The previous prime is 21652551181. The next prime is 21652551227. The reversal of 21652551221 is 12215525612.

It is a happy number.

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 21652551221 - 2³⁰ = 20578809397 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 (21652551227) 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, 81400436 + ... + 81400701.

It is an arithmetic number, because the mean of its divisors is an integer number (3256022760).

Almost surely, 2^21652551221 is an apocalyptic number.

It is an amenable number.

21652551221 is a deficient number, since it is larger than the sum of its proper divisors (4395630859).

21652551221 is a wasteful number, since it uses less digits than its factorization.

21652551221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162801163.

The product of its digits is 12000, while the sum is 32.

The spelling of 21652551221 in words is "twenty-one billion, six hundred fifty-two million, five hundred fifty-one thousand, two hundred twenty-one".