21418125851 has 2 divisors, whose sum is σ = 21418125852. Its totient is φ = 21418125850.

The previous prime is 21418125823. The next prime is 21418125853. The reversal of 21418125851 is 15852181412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21418125851 - 2²⁶ = 21351016987 is a prime.

It is a super-2 number, since 2×21418125851² (a number of 21 digits) contains 22 as substring.

Together with 21418125853, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21418125853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709062925 + 10709062926.

It is an arithmetic number, because the mean of its divisors is an integer number (10709062926).

Almost surely, 2^21418125851 is an apocalyptic number.

21418125851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418125851 is an equidigital number, since it uses as much as digits as its factorization.

21418125851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25600, while the sum is 38.

The spelling of 21418125851 in words is "twenty-one billion, four hundred eighteen million, one hundred twenty-five thousand, eight hundred fifty-one".