21345001 has 2 divisors, whose sum is σ = 21345002. Its totient is φ = 21345000.

The previous prime is 21344987. The next prime is 21345007. The reversal of 21345001 is 10054312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14055001 + 7290000 = 3749^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 21345001 - 2¹¹ = 21342953 is a prime.

It is not a weakly prime, because it can be changed into another prime (21345007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672500 + 10672501.

It is an arithmetic number, because the mean of its divisors is an integer number (10672501).

Almost surely, 2^21345001 is an apocalyptic number.

It is an amenable number.

21345001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345001 is an equidigital number, since it uses as much as digits as its factorization.

21345001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21345001 is about 4620.0650428322. The cubic root of 21345001 is about 277.3950624517.

Adding to 21345001 its reverse (10054312), we get a palindrome (31399313).

The spelling of 21345001 in words is "twenty-one million, three hundred forty-five thousand, one".