21311175547 has 2 divisors, whose sum is σ = 21311175548. Its totient is φ = 21311175546.

The previous prime is 21311175517. The next prime is 21311175559. The reversal of 21311175547 is 74557111312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21311175547 - 2¹⁹ = 21310651259 is a prime.

It is not a weakly prime, because it can be changed into another prime (21311175517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655587773 + 10655587774.

It is an arithmetic number, because the mean of its divisors is an integer number (10655587774).

Almost surely, 2^21311175547 is an apocalyptic number.

21311175547 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311175547 is an equidigital number, since it uses as much as digits as its factorization.

21311175547 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29400, while the sum is 37.

Adding to 21311175547 its reverse (74557111312), we get a palindrome (95868286859).

The spelling of 21311175547 in words is "twenty-one billion, three hundred eleven million, one hundred seventy-five thousand, five hundred forty-seven".