21418403 has 2 divisors, whose sum is σ = 21418404. Its totient is φ = 21418402.

The previous prime is 21418379. The next prime is 21418409. The reversal of 21418403 is 30481412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21418403 - 2¹⁴ = 21402019 is a prime.

It is not a weakly prime, because it can be changed into another prime (21418409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10709201 + 10709202.

It is an arithmetic number, because the mean of its divisors is an integer number (10709202).

Almost surely, 2^21418403 is an apocalyptic number.

21418403 is a deficient number, since it is larger than the sum of its proper divisors (1).

21418403 is an equidigital number, since it uses as much as digits as its factorization.

21418403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21418403 is about 4628.0020527221. The cubic root of 21418403 is about 277.7126708863.

Adding to 21418403 its reverse (30481412), we get a palindrome (51899815).

The spelling of 21418403 in words is "twenty-one million, four hundred eighteen thousand, four hundred three".