21135424541 has 16 divisors (see below), whose sum is σ = 26355639168. Its totient is φ = 16466049600.

The previous prime is 21135424487. The next prime is 21135424561. The reversal of 21135424541 is 14542453112.

It is a de Polignac number, because none of the positive numbers 2^k-21135424541 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21135424498 and 21135424507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135424561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 437591 + ... + 483483.

It is an arithmetic number, because the mean of its divisors is an integer number (1647227448).

Almost surely, 2^21135424541 is an apocalyptic number.

It is an amenable number.

21135424541 is a deficient number, since it is larger than the sum of its proper divisors (5220214627).

21135424541 is a wasteful number, since it uses less digits than its factorization.

21135424541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51892.

The product of its digits is 19200, while the sum is 32.

Adding to 21135424541 its reverse (14542453112), we get a palindrome (35677877653).

The spelling of 21135424541 in words is "twenty-one billion, one hundred thirty-five million, four hundred twenty-four thousand, five hundred forty-one".