21522540505 has 4 divisors (see below), whose sum is σ = 25827048612. Its totient is φ = 17218032400.

The previous prime is 21522540419. The next prime is 21522540509. The reversal of 21522540505 is 50504522512.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10926102784 + 10596437721 = 104528^2 + 102939^2 .

It is not a de Polignac number, because 21522540505 - 2¹⁵ = 21522507737 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21522540509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2152254046 + ... + 2152254055.

It is an arithmetic number, because the mean of its divisors is an integer number (6456762153).

Almost surely, 2^21522540505 is an apocalyptic number.

It is an amenable number.

21522540505 is a deficient number, since it is larger than the sum of its proper divisors (4304508107).

21522540505 is an equidigital number, since it uses as much as digits as its factorization.

21522540505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4304508106.

The product of its (nonzero) digits is 20000, while the sum is 31.

The spelling of 21522540505 in words is "twenty-one billion, five hundred twenty-two million, five hundred forty thousand, five hundred five".