21136436545 has 16 divisors (see below), whose sum is σ = 29013304320. Its totient is φ = 14480460864.

The previous prime is 21136436507. The next prime is 21136436579. The reversal of 21136436545 is 54563463112.

It is a cyclic number.

It is not a de Polignac number, because 21136436545 - 2⁷ = 21136436417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21136436498 and 21136436507.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 233457 + ... + 311086.

It is an arithmetic number, because the mean of its divisors is an integer number (1813331520).

Almost surely, 2^21136436545 is an apocalyptic number.

It is an amenable number.

21136436545 is a deficient number, since it is larger than the sum of its proper divisors (7876867775).

21136436545 is a wasteful number, since it uses less digits than its factorization.

21136436545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545664.

The product of its digits is 259200, while the sum is 40.

Adding to 21136436545 its reverse (54563463112), we get a palindrome (75699899657).

The spelling of 21136436545 in words is "twenty-one billion, one hundred thirty-six million, four hundred thirty-six thousand, five hundred forty-five".