21000212021251 has 2 divisors, whose sum is σ = 21000212021252. Its totient is φ = 21000212021250.

The previous prime is 21000212021203. The next prime is 21000212021287. The reversal of 21000212021251 is 15212021200012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000212021251 - 2⁷ = 21000212021123 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000212021291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500106010625 + 10500106010626.

It is an arithmetic number, because the mean of its divisors is an integer number (10500106010626).

Almost surely, 2^{21000212021251} is an apocalyptic number.

21000212021251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000212021251 is an equidigital number, since it uses as much as digits as its factorization.

21000212021251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 19.

Adding to 21000212021251 its reverse (15212021200012), we get a palindrome (36212233221263).

The spelling of 21000212021251 in words is "twenty-one trillion, two hundred twelve million, twenty-one thousand, two hundred fifty-one".