21345164443 has 2 divisors, whose sum is σ = 21345164444. Its totient is φ = 21345164442.

The previous prime is 21345164429. The next prime is 21345164549. The reversal of 21345164443 is 34446154312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21345164443 is a prime.

It is not a weakly prime, because it can be changed into another prime (21345164143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672582221 + 10672582222.

It is an arithmetic number, because the mean of its divisors is an integer number (10672582222).

Almost surely, 2^21345164443 is an apocalyptic number.

21345164443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345164443 is an equidigital number, since it uses as much as digits as its factorization.

21345164443 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 37.

The spelling of 21345164443 in words is "twenty-one billion, three hundred forty-five million, one hundred sixty-four thousand, four hundred forty-three".