194217421 has 2 divisors, whose sum is σ = 194217422. Its totient is φ = 194217420.

The previous prime is 194217407. The next prime is 194217431. The reversal of 194217421 is 124712491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122899396 + 71318025 = 11086^2 + 8445^2 .

It is an emirp because it is prime and its reverse (124712491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 194217421 - 2⁷ = 194217293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194217431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97108710 + 97108711.

It is an arithmetic number, because the mean of its divisors is an integer number (97108711).

Almost surely, 2^194217421 is an apocalyptic number.

It is an amenable number.

194217421 is a deficient number, since it is larger than the sum of its proper divisors (1).

194217421 is an equidigital number, since it uses as much as digits as its factorization.

194217421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 31.

The square root of 194217421 is about 13936.1910506422. The cubic root of 194217421 is about 579.1122179017.

The spelling of 194217421 in words is "one hundred ninety-four million, two hundred seventeen thousand, four hundred twenty-one".