21435493 has 2 divisors, whose sum is σ = 21435494. Its totient is φ = 21435492.

The previous prime is 21435481. The next prime is 21435499. The reversal of 21435493 is 39453412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16136289 + 5299204 = 4017^2 + 2302^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21435493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21435499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717746 + 10717747.

It is an arithmetic number, because the mean of its divisors is an integer number (10717747).

Almost surely, 2^21435493 is an apocalyptic number.

It is an amenable number.

21435493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21435493 is an equidigital number, since it uses as much as digits as its factorization.

21435493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 31.

The square root of 21435493 is about 4629.8480536622. The cubic root of 21435493 is about 277.7865146704.

The spelling of 21435493 in words is "twenty-one million, four hundred thirty-five thousand, four hundred ninety-three".