21420140351 has 2 divisors, whose sum is σ = 21420140352. Its totient is φ = 21420140350.

The previous prime is 21420140321. The next prime is 21420140353. The reversal of 21420140351 is 15304102412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21420140351 is a prime.

Together with 21420140353, 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 (21420140353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10710070175 + 10710070176.

It is an arithmetic number, because the mean of its divisors is an integer number (10710070176).

Almost surely, 2^21420140351 is an apocalyptic number.

21420140351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420140351 is an equidigital number, since it uses as much as digits as its factorization.

21420140351 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21420140351 its reverse (15304102412), we get a palindrome (36724242763).

The spelling of 21420140351 in words is "twenty-one billion, four hundred twenty million, one hundred forty thousand, three hundred fifty-one".