17421421 has 2 divisors, whose sum is σ = 17421422. Its totient is φ = 17421420.

The previous prime is 17421367. The next prime is 17421449. The reversal of 17421421 is 12412471.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11594025 + 5827396 = 3405^2 + 2414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-17421421 is a prime.

It is equal to p_1116643 and since 17421421 and 1116643 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 17421392 and 17421401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17421221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8710710 + 8710711.

It is an arithmetic number, because the mean of its divisors is an integer number (8710711).

Almost surely, 2^17421421 is an apocalyptic number.

It is an amenable number.

17421421 is a deficient number, since it is larger than the sum of its proper divisors (1).

17421421 is an equidigital number, since it uses as much as digits as its factorization.

17421421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 448, while the sum is 22.

The square root of 17421421 is about 4173.8975790021. The cubic root of 17421421 is about 259.2355305930.

Adding to 17421421 its reverse (12412471), we get a palindrome (29833892).

The spelling of 17421421 in words is "seventeen million, four hundred twenty-one thousand, four hundred twenty-one".