21203231087 has 2 divisors, whose sum is σ = 21203231088. Its totient is φ = 21203231086.

The previous prime is 21203231059. The next prime is 21203231167. The reversal of 21203231087 is 78013230212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21203231087 - 2¹² = 21203226991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203237087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601615543 + 10601615544.

It is an arithmetic number, because the mean of its divisors is an integer number (10601615544).

Almost surely, 2^21203231087 is an apocalyptic number.

21203231087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203231087 is an equidigital number, since it uses as much as digits as its factorization.

21203231087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 29.

Adding to 21203231087 its reverse (78013230212), we get a palindrome (99216461299).

The spelling of 21203231087 in words is "twenty-one billion, two hundred three million, two hundred thirty-one thousand, eighty-seven".