21205337159087 has 2 divisors, whose sum is σ = 21205337159088. Its totient is φ = 21205337159086.

The previous prime is 21205337159051. The next prime is 21205337159089. The reversal of 21205337159087 is 78095173350212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21205337159087 is a prime.

Together with 21205337159089, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21205337159089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602668579543 + 10602668579544.

It is an arithmetic number, because the mean of its divisors is an integer number (10602668579544).

Almost surely, 2^{21205337159087} is an apocalyptic number.

21205337159087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21205337159087 is an equidigital number, since it uses as much as digits as its factorization.

21205337159087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3175200, while the sum is 53.

The spelling of 21205337159087 in words is "twenty-one trillion, two hundred five billion, three hundred thirty-seven million, one hundred fifty-nine thousand, eighty-seven".