20817403 has 2 divisors, whose sum is σ = 20817404. Its totient is φ = 20817402.

The previous prime is 20817373. The next prime is 20817427. The reversal of 20817403 is 30471802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20817403 is a prime.

It is not a weakly prime, because it can be changed into another prime (20817443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10408701 + 10408702.

It is an arithmetic number, because the mean of its divisors is an integer number (10408702).

Almost surely, 2^20817403 is an apocalyptic number.

20817403 is a deficient number, since it is larger than the sum of its proper divisors (1).

20817403 is an equidigital number, since it uses as much as digits as its factorization.

20817403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 20817403 is about 4562.6092315691. The cubic root of 20817403 is about 275.0904517884.

Subtracting from 20817403 its sum of digits (25), we obtain a triangular number (20817378 = T₆₄₅₂).

The spelling of 20817403 in words is "twenty million, eight hundred seventeen thousand, four hundred three".