21012000030251 has 2 divisors, whose sum is σ = 21012000030252. Its totient is φ = 21012000030250.

The previous prime is 21012000030221. The next prime is 21012000030283. The reversal of 21012000030251 is 15203000021012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012000030251 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012000030221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506000015125 + 10506000015126.

It is an arithmetic number, because the mean of its divisors is an integer number (10506000015126).

Almost surely, 2^{21012000030251} is an apocalyptic number.

21012000030251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012000030251 is an equidigital number, since it uses as much as digits as its factorization.

21012000030251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 17.

Adding to 21012000030251 its reverse (15203000021012), we get a palindrome (36215000051263).

The spelling of 21012000030251 in words is "twenty-one trillion, twelve billion, thirty thousand, two hundred fifty-one".