21541522231 has 4 divisors (see below), whose sum is σ = 21705961464. Its totient is φ = 21377083000.

The previous prime is 21541522207. The next prime is 21541522243. The reversal of 21541522231 is 13222514512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21541522231 - 2¹¹ = 21541520183 is a prime.

It is a super-2 number, since 2×21541522231² (a number of 21 digits) contains 22 as substring.

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 21541522231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21541522291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82219420 + ... + 82219681.

It is an arithmetic number, because the mean of its divisors is an integer number (5426490366).

Almost surely, 2^21541522231 is an apocalyptic number.

21541522231 is a deficient number, since it is larger than the sum of its proper divisors (164439233).

21541522231 is a wasteful number, since it uses less digits than its factorization.

21541522231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164439232.

The product of its digits is 4800, while the sum is 28.

The spelling of 21541522231 in words is "twenty-one billion, five hundred forty-one million, five hundred twenty-two thousand, two hundred thirty-one".