21152520043345 has 8 divisors (see below), whose sum is σ = 25383970175976. Its totient is φ = 16921385285376.

The previous prime is 21152520043331. The next prime is 21152520043373. The reversal of 21152520043345 is 54334002525112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1029723651009 + 20122796392336 = 1014753^2 + 4485844^2 .

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 21152520043345 - 2¹⁵ = 21152520010577 is a prime.

It is a super-2 number, since 2×21152520043345² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78696082 + ... + 78964411.

It is an arithmetic number, because the mean of its divisors is an integer number (3172996271997).

Almost surely, 2^{21152520043345} is an apocalyptic number.

It is an amenable number.

21152520043345 is a deficient number, since it is larger than the sum of its proper divisors (4231450132631).

21152520043345 is a wasteful number, since it uses less digits than its factorization.

21152520043345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157687331.

The product of its (nonzero) digits is 144000, while the sum is 37.

Adding to 21152520043345 its reverse (54334002525112), we get a palindrome (75486522568457).

The spelling of 21152520043345 in words is "twenty-one trillion, one hundred fifty-two billion, five hundred twenty million, forty-three thousand, three hundred forty-five".