21001112210251 has 2 divisors, whose sum is σ = 21001112210252. Its totient is φ = 21001112210250.

The previous prime is 21001112210159. The next prime is 21001112210269. The reversal of 21001112210251 is 15201221110012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001112210251 - 2⁹ = 21001112209739 is a prime.

It is not a weakly prime, because it can be changed into another prime (21001112280251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500556105125 + 10500556105126.

It is an arithmetic number, because the mean of its divisors is an integer number (10500556105126).

Almost surely, 2^{21001112210251} is an apocalyptic number.

21001112210251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001112210251 is an equidigital number, since it uses as much as digits as its factorization.

21001112210251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 19.

Adding to 21001112210251 its reverse (15201221110012), we get a palindrome (36202333320263).

The spelling of 21001112210251 in words is "twenty-one trillion, one billion, one hundred twelve million, two hundred ten thousand, two hundred fifty-one".