21536243501 has 16 divisors (see below), whose sum is σ = 23351456304. Its totient is φ = 19785851904.

The previous prime is 21536243489. The next prime is 21536243527. The reversal of 21536243501 is 10534263512.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3684611401 + 17851632100 = 60701^2 + 133610^2 .

It is a cyclic number.

It is not a de Polignac number, because 21536243501 - 2¹⁰ = 21536242477 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 (21536233501) 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 15 ways as a sum of consecutive naturals, for example, 116831 + ... + 238163.

It is an arithmetic number, because the mean of its divisors is an integer number (1459466019).

Almost surely, 2^21536243501 is an apocalyptic number.

It is an amenable number.

21536243501 is a deficient number, since it is larger than the sum of its proper divisors (1815212803).

21536243501 is a wasteful number, since it uses less digits than its factorization.

21536243501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121600.

The product of its (nonzero) digits is 21600, while the sum is 32.

The spelling of 21536243501 in words is "twenty-one billion, five hundred thirty-six million, two hundred forty-three thousand, five hundred one".