21113353506251 has 2 divisors, whose sum is σ = 21113353506252. Its totient is φ = 21113353506250.

The previous prime is 21113353506227. The next prime is 21113353506283. The reversal of 21113353506251 is 15260535331112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21113353506251 - 2¹⁴ = 21113353489867 is a prime.

It is not a weakly prime, because it can be changed into another prime (21113353506211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556676753125 + 10556676753126.

It is an arithmetic number, because the mean of its divisors is an integer number (10556676753126).

Almost surely, 2^{21113353506251} is an apocalyptic number.

21113353506251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113353506251 is an equidigital number, since it uses as much as digits as its factorization.

21113353506251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81000, while the sum is 38.

Adding to 21113353506251 its reverse (15260535331112), we get a palindrome (36373888837363).

The spelling of 21113353506251 in words is "twenty-one trillion, one hundred thirteen billion, three hundred fifty-three million, five hundred six thousand, two hundred fifty-one".