21102111287 has 2 divisors, whose sum is σ = 21102111288. Its totient is φ = 21102111286.

The previous prime is 21102111263. The next prime is 21102111337. The reversal of 21102111287 is 78211120112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21102111287 - 2⁶ = 21102111223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102111257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551055643 + 10551055644.

It is an arithmetic number, because the mean of its divisors is an integer number (10551055644).

Almost surely, 2^21102111287 is an apocalyptic number.

21102111287 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102111287 is an equidigital number, since it uses as much as digits as its factorization.

21102111287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 26.

Adding to 21102111287 its reverse (78211120112), we get a palindrome (99313231399).

The spelling of 21102111287 in words is "twenty-one billion, one hundred two million, one hundred eleven thousand, two hundred eighty-seven".