21012112201987 has 2 divisors, whose sum is σ = 21012112201988. Its totient is φ = 21012112201986.

The previous prime is 21012112201939. The next prime is 21012112202027. The reversal of 21012112201987 is 78910221121012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012112201987 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012112201687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506056100993 + 10506056100994.

It is an arithmetic number, because the mean of its divisors is an integer number (10506056100994).

Almost surely, 2^{21012112201987} is an apocalyptic number.

21012112201987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012112201987 is an equidigital number, since it uses as much as digits as its factorization.

21012112201987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 37.

Adding to 21012112201987 its reverse (78910221121012), we get a palindrome (99922333322999).

The spelling of 21012112201987 in words is "twenty-one trillion, twelve billion, one hundred twelve million, two hundred one thousand, nine hundred eighty-seven".