21020111234951 has 2 divisors, whose sum is σ = 21020111234952. Its totient is φ = 21020111234950.

The previous prime is 21020111234887. The next prime is 21020111234953. The reversal of 21020111234951 is 15943211102012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21020111234951 - 2⁶ = 21020111234887 is a prime.

Together with 21020111234953, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21020111234953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510055617475 + 10510055617476.

It is an arithmetic number, because the mean of its divisors is an integer number (10510055617476).

Almost surely, 2^{21020111234951} is an apocalyptic number.

21020111234951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020111234951 is an equidigital number, since it uses as much as digits as its factorization.

21020111234951 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 32.

Adding to 21020111234951 its reverse (15943211102012), we get a palindrome (36963322336963).

The spelling of 21020111234951 in words is "twenty-one trillion, twenty billion, one hundred eleven million, two hundred thirty-four thousand, nine hundred fifty-one".