21351431663459 has 2 divisors, whose sum is σ = 21351431663460. Its totient is φ = 21351431663458.

The previous prime is 21351431663251. The next prime is 21351431663461. The reversal of 21351431663459 is 95436613415312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21351431663459 - 2⁸ = 21351431663203 is a prime.

Together with 21351431663461, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21351431663459.

It is not a weakly prime, because it can be changed into another prime (21351431663059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675715831729 + 10675715831730.

It is an arithmetic number, because the mean of its divisors is an integer number (10675715831730).

Almost surely, 2^{21351431663459} is an apocalyptic number.

21351431663459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351431663459 is an equidigital number, since it uses as much as digits as its factorization.

21351431663459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6998400, while the sum is 53.

The spelling of 21351431663459 in words is "twenty-one trillion, three hundred fifty-one billion, four hundred thirty-one million, six hundred sixty-three thousand, four hundred fifty-nine".