213661522505 has 8 divisors (see below), whose sum is σ = 256398275400. Its totient is φ = 170926252416.

The previous prime is 213661522471. The next prime is 213661522507. The reversal of 213661522505 is 505225166312.

213661522505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7155806464 + 206505716041 = 84592^2 + 454429^2 .

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 213661522505 - 2⁶ = 213661522441 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (213661522507) 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 7 ways as a sum of consecutive naturals, for example, 24260 + ... + 654149.

It is an arithmetic number, because the mean of its divisors is an integer number (32049784425).

Almost surely, 2^213661522505 is an apocalyptic number.

It is an amenable number.

213661522505 is a deficient number, since it is larger than the sum of its proper divisors (42736752895).

213661522505 is an equidigital number, since it uses as much as digits as its factorization.

213661522505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 741403.

The product of its (nonzero) digits is 108000, while the sum is 38.

Adding to 213661522505 its reverse (505225166312), we get a palindrome (718886688817).

The spelling of 213661522505 in words is "two hundred thirteen billion, six hundred sixty-one million, five hundred twenty-two thousand, five hundred five".