21111021010687 has 2 divisors, whose sum is σ = 21111021010688. Its totient is φ = 21111021010686.

The previous prime is 21111021010633. The next prime is 21111021010691. The reversal of 21111021010687 is 78601012011112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111021010687 is a prime.

It is a super-2 number, since 2×21111021010687² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111021010697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555510505343 + 10555510505344.

It is an arithmetic number, because the mean of its divisors is an integer number (10555510505344).

Almost surely, 2^{21111021010687} is an apocalyptic number.

21111021010687 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111021010687 is an equidigital number, since it uses as much as digits as its factorization.

21111021010687 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 31.

Adding to 21111021010687 its reverse (78601012011112), we get a palindrome (99712033021799).

The spelling of 21111021010687 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, ten thousand, six hundred eighty-seven".