21115431541 has 8 divisors (see below), whose sum is σ = 21882365280. Its totient is φ = 20351085552.

The previous prime is 21115431539. The next prime is 21115431563. The reversal of 21115431541 is 14513451112.

It is a happy number.

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 21115431541 - 2¹ = 21115431539 is a prime.

It is a super-2 number, since 2×21115431541² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115431511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 630315 + ... + 662968.

It is an arithmetic number, because the mean of its divisors is an integer number (2735295660).

Almost surely, 2^21115431541 is an apocalyptic number.

It is an amenable number.

21115431541 is a deficient number, since it is larger than the sum of its proper divisors (766933739).

21115431541 is a wasteful number, since it uses less digits than its factorization.

21115431541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1293875.

The product of its digits is 2400, while the sum is 28.

Adding to 21115431541 its reverse (14513451112), we get a palindrome (35628882653).

The spelling of 21115431541 in words is "twenty-one billion, one hundred fifteen million, four hundred thirty-one thousand, five hundred forty-one".