21205336027 has 2 divisors, whose sum is σ = 21205336028. Its totient is φ = 21205336026.

The previous prime is 21205335973. The next prime is 21205336037. The reversal of 21205336027 is 72063350212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21205336027 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21205336027.

It is not a weakly prime, because it can be changed into another prime (21205336037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602668013 + 10602668014.

It is an arithmetic number, because the mean of its divisors is an integer number (10602668014).

Almost surely, 2^21205336027 is an apocalyptic number.

21205336027 is a deficient number, since it is larger than the sum of its proper divisors (1).

21205336027 is an equidigital number, since it uses as much as digits as its factorization.

21205336027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 31.

Adding to 21205336027 its reverse (72063350212), we get a palindrome (93268686239).

The spelling of 21205336027 in words is "twenty-one billion, two hundred five million, three hundred thirty-six thousand, twenty-seven".